Suleyman Ozcelik - Profile on Academia.edu (original) (raw)
Papers by Suleyman Ozcelik
Semiconductors, Oct 1, 2013
The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in A... more The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in Au/SiO 2 /n-GaAs metal-insulator-semiconductor type Schottky contacts. Reverse-bias current-voltage measurements (I-V ) were performed at room temperature. The using of leakage current values in SiO 2 at electric fields of 1.46-3.53 MV/cm, ln(J/E) vs. √ E graph showed good linearity. From this plot, dielectric constant of SiO 2 was calculated as 3.7 and this value is perfect agreement with 3.9 which is value of SiO 2 dielectric constant. This indicates, Poole-Frenkel type emission mechanism is dominant in this field region. On the other hand, electric fields between 0.06-0.73 and 0.79-1.45 MV/cm, dominant leakage current mechanisms were found as ohmic type conduction and space charge limited conduction, respectively.
Politeknik dergisi, Jun 1, 2020
In this study, InGaN/GaN structures are grown by using Metal Organic Chemical Vapor Deposition (M... more In this study, InGaN/GaN structures are grown by using Metal Organic Chemical Vapor Deposition (MOCVD) technique. Some structural, optical and morphological properties of InGaN/GaN structures are investigated in detail. For structural analysis, X-ray diffraction (XRD), for optical, Raman and morphological, Atomic Force Microscopy (AFM) measurement techniques are used. In XRD analysis both samples presented hexagonal crystal structure. XRD peaks for these two samples showed small differences dependent on growth conditions. Strain and stress values are determined from XRD and they are compared with Raman results. In Raman analysis, five different chemicals are determined in both samples. Raman analysis results are in good accordance with XRD, growth conditions and AFM images. In AFM images, there can be seen hills and holes and they are partly homogeneous. There are also some white regions in AFM images. According to Raman peak center data, these white regions are detected as white rust.
Beyaz Led uygulamaları için InGaN LED yapılarınanalizi
Politeknik dergisi, 2017
Structural, morphological, optical and electrical properties of the Ti doped-ZnO (TZO) thin film prepared by RF sputter technique
Physica B-condensed Matter, Sep 1, 2021
Abstract In this study, the structural, morphological, optical, as well as electrical properties ... more Abstract In this study, the structural, morphological, optical, as well as electrical properties of the titanium doped (wt 5%) ZnO (TZO) thin film grown with the RF sputtering system was examined. TZO thin films were deposited on both corning glass (CG) and n–type Si substrates. It was determined that the TZO thin film deposited on CG has crystallinity, good surface homogeneity, low surface roughness as well as suitable band gap value from X–Ray diffraction (XRD), atomic force microscopy (AFM) as well as UV–Vis analysis. In addition, TZO thin film deposited on the n–Si substrate was used to determine the electrical properties. The current–voltage (I–V) measurements of the Au/TZO/n–Si structure was done at 80 K and 300 K. Capacitance–voltage ( C – V ) and conductance–voltage ( G / ω – V ) measurements of the Au/TZO/n–Si structure was examined for 0.3, 0.5 and 1 MHz.
Physica B-condensed Matter, Jun 1, 2007
The current-voltage (I-V) measurements on Al/ZnS Schottky barrier diodes in the temperature range... more The current-voltage (I-V) measurements on Al/ZnS Schottky barrier diodes in the temperature range 303 -423 K by the step of 15 K were carried out. The forward I-V characteristics were analyzed on the basis of the thermionic emission theory. The temperature dependence I-V parameters such as ideality factor (n) and barrier height ( b0 ) have been explained on the basis of inhomogeneity. An abnormal increase of apparent barrier height and decrease of ideality factor with increasing temperature have been explained due to the barrier height inhomogeneities on the basis of the thermionic emission theory with Gaussian distribution. Experimental results reveal the existence of a single Gaussian distribution with apparent barrier height value ( ) of 1.091 eV and standard deviations ( s ) of 0.18 V. Richardson constant (A*) was obtained as 8.49 x 10 -2 A.m -2 K -2 from the ln(I 0 /T 2 ) vs. q/kT plot, which is far from the calculated value of 5.6 x 10 5 A.m -2 K -2 . The modified Richardson plotof ln(I 0 /T 2 ) -(q 2 s 2 /2k 2 T 2 ) gives and A* values as 1.093 eV and 6.07 x 10 5 A.m -2 K -2 , without using the temperature coefficient of the barrier height. This obtained value of A* is extremely close to the previously calculated value. So, the temperature dependence of the forward bias I-V characteristics of the Schottky device can be successfully explained on the basis of the thermionic emission mechanism with a single Gaussian distribution of the barrier heights.
Optik, Sep 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Physica B-condensed Matter, Feb 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Au and non-Au based rare earth metal-silicide ohmic contacts to p-InGaAs
Solid-state Electronics, Jul 1, 2011
ABSTRACT The aim of this study is to improve the electrical properties of ohmic contacts that pla... more ABSTRACT The aim of this study is to improve the electrical properties of ohmic contacts that plays crucial role on the performance of optoelectronic devices such as laser diodes (LDs), light emitting diodes (LEDs) and photodetectors (PDs). The conventional (Pd/Ir/Au, Ti/Pt/Au and Pt/Ti/Pt/Au), Au and non-Au based rare earth metal-silicide ohmic contacts (Gd/Si/Ti/Au, Gd/Si/Pt/Au and Gd/Si/Pt) to p-InGaAs were investigated and compared each other. To calculate the specific contact resistivities the Transmission Line Model (TLM) was used. Minimum specific contact resistivity of the conventional contacts was found as 0.111 × 10−6 Ω cm2 for Pt/Ti/Pt/Au contact at 400 °C annealing temperature. For the rare earth metal-silicide ohmic contacts, the non-Au based Gd/Si/Pt has the minimum value of 4.410 × 10−6 Ω cm2 at 300 °C annealing temperature. As a result, non-Au based Gd/Si/Pt contact shows the best ohmic contact behavior at a relatively low annealing temperature among the rare earth metal-silicide ohmic contacts. Although the Au based conventional ohmic contacts are thermally stable and have lower noise in electronic circuits, by using the non-Au based rare earth metal-silicide ohmic contacts may overcome the problems of Au-based ohmic contacts such as higher cost, poorer reliability, weaker thermal stability, and the device degradation due to relatively higher alloying temperatures. To the best of our knowledge, the Au and non-Au based rare earth metal-silicide (GdSix) ohmic contacts to p-InGaAs have been proposed for the first time.
Journal of Applied Physics, Mar 12, 2014
Three InGaAs/InP structures for photodetector applications were grown with different indium compo... more Three InGaAs/InP structures for photodetector applications were grown with different indium compositions by MBE technique. The structural properties of the samples have been obtained by means of high resolution X-ray diffraction and secondary ion mass spectrometry measurements. Three InGaAs/InP metal-semiconductor-metal devices were fabricated at room temperature. The experimental forward and reverse bias current-voltage characteristics of the devices such as ideality factor, barrier height, and saturation current were evaluated considering the structural properties of the grown structures. The carrier recombination lifetime and diffusion length in the devices were also calculated using carrier density and mobility data obtained with Hall effect measurement at room temperature. It was determined that all room temperature fabricated devices improved the Schottky barrier height. Especially, the device fabricated on the lower mismatched structure exhibited barrier height enhancement from 0.2 eV, which is the conventional barrier height to 0.642 eV. In addition, the obtained results show that the room temperature fabricated devices on InGaAs/InP structures can be convenient for infrared photodetector applications.
SEMICONDUCTOR STRUCTURES, LOWDIMENSIONAL SYSTEMS, AND QUANTUM PHENOMENA The Analysis of Leakage Current in MIS Au/SiO 2 /nGaAs at Room Temperature 1
On the frequency-dependent complex-dielectric, complex-electric modulus and conductivity in Au/(NiS:PVP)/n-Si structures
Journal of Materials Science: Materials in Electronics, Jul 17, 2021
The values of complex-dielectric (ε* = ε′ − jε″), loss-tangent (tanδ), complex-electric modulus (... more The values of complex-dielectric (ε* = ε′ − jε″), loss-tangent (tanδ), complex-electric modulus (M* = M′ + jM″), and ac electrical-conductivity (σac) of the performed Au/(NiS:PVP)/n-Si structures were extracted from the measured impedance-spectroscopy method (ISM) in frequency range of 10 kHz–1 MHz and voltage ((− 2 V)–(+ 3 V)). These parameters, which constitute the main subject of our study, have been obtained from high frequency and voltage values, more particularly in the depletion and accumulation regions. The decrease of dielectric-constant (ε′), dielectric-loss (ε″), and tanδ with increasing frequency for almost every voltage were explained by Maxwell–Wagner type relaxation processes. The observed higher-values of ε′ and ε″ at low frequencies result from surface-states (Nss) and dipole-polarization. Since Nss has sufficient time to keep up with the applied voltage signal, dipoles can respond to the electric field to reorient themselves. An increase in M′ values was observed at increasing frequency values attributed to the long-distance mobility of the carriers. On the other hand, the observed peak in the M″ − ln (f) curves was attributed to a distinctive distribution of Nss located at Au/(NiS:PVP) interface depend on their lifetime. The obtained value of ε′ even at 10 kHz at 3 V is indicated that the used (NiS:PVP) organic-interlayer can be used a superior alternative instead of SiO2 or SnO2 which are conventional interlayers thanks to its low-cost, flexibility, easy production techniques such as spin-coating or electro-spinning technique at room condition, successfully.
Analysis of temperature dependent electrical characteristics of Au/n-GaAs/GaAs structures in a wide temperature range
Vacuum, Sep 1, 2008
The temperature dependence of some electrical parameters of Au/n-GaAs/GaAs structures obtained fr... more The temperature dependence of some electrical parameters of Au/n-GaAs/GaAs structures obtained from the forward bias current–voltage (I–V) and reverse bias capacitance–voltage (C–V) characteristics is studied in the temperature range of 79–400K. The forward bias current I is found to be proportional to Io(T)exp(AV), where A is the slope of Ln(I)–V curves and almost independent of the voltage and temperature, and
Determination of surface morphology and electrical properties of MoO3 layer deposited on GaAs substrate with RF magnetron sputtering
Journal of Materials Science: Materials in Electronics, Apr 9, 2021
We report the effects of the substrate temperature on the surface morphology of Molybdenum tri-ox... more We report the effects of the substrate temperature on the surface morphology of Molybdenum tri-oxide (MoO3) thin films and the electrically detailed examination of Au/MoO3/n–GaAs MOS heterojunction structure with the best homogeneity. MoO3 thin film was deposited both on soda–lime silicate glass as a thin film and n-type and (100) oriented GaAs substrates using RF magnetron sputtering method at substrate temperatures of room temperature, 100 °C, 200 °C and 300 °C. Surface morphology of the MoO3 thin films were investigated by utilizing atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements. AFM and SEM results have shown that MoO3 thin film with substrate temperature of 200 °C has the lowest surface roughness and the homogeneity of the film structures significantly enhances with increasing substrate temperature up to 200 °C. An inclement in roughness of thin film structure was detected at higher temperature than 200 °C due to the deterioration of homogeneity. Therefore, we primarily focused on the MoO3 thin films produced at the substrate temperature of 200 °C to examine the electrical properties of Au/MoO3/n–GaAs MOS heterojunction device. In order to determine the electrical properties, temperature dependent I-V\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I-V$$\end{document} measurements were performed in between 200 and 400 K by steps of 25 K. The fundamental electrical parameters such as saturation current (I0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${I}_{0}$$\end{document}), ideality factor (n\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n$$\end{document}), and barrier height (ϕ0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\phi }_{0}$$\end{document}) were calculated by analyzing the forward bias I-V\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I{-}V$$\end{document} curves at different temperatures. The series resistance (Rs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{s}$$\end{document}) values of the device were also determined using the plot of structure resistance (Ri\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{\text{i}}$$\end{document}) vs applied bias voltage (Vi\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${V}_{i}$$\end{document}), Thermionic Emission Theory and Cheung and Cheung methods. The Rs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{s}$$\end{document} value of Au/MoO3/n–GaAs MOS heterojunction device shows an abnormal behavior of up to 350 K, which is the critical temperature value and tends to increase with increasing temperature. Above the critical temperature value, it exhibits ideal behavior.
Temperature dependence of electrical characteristics and interface state densities of Au/n-type Si structures with SnS doped PVC interface
Physica Scripta, Aug 24, 2022
Frequency and voltage-dependent electrical parameters, interface traps, and series resistance profile of Au/(NiS:PVP)/n-Si structures
Journal of Materials Science: Materials in Electronics, May 1, 2021
A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact w... more A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact were prepared on the surface by the sputtering method and then their basic electrical features for example diffusion-potential (VD), doping density of donor-atoms (ND), Fermi-energy (EF), barrier-height (ΦB), and depletion layer-width (WD) were extracted reverse-bias C-2-V plots as function frequency and voltage. The voltage profile of interface/surface-states (Nss)/ relaxation-times (τ), and series resistance (Rs) were also obtained from the admittance and Nicollian-Brews method, respectively. Strongly frequency-dependent and voltage especially in both accumulation and depletion regions due to the existence of Nss, Rs, and polarization as well as (NiS-doped PVP) organic interlayer. At low frequency, the observed higher value of C and G shows that thin (NiS:PVP) interlayer can be successfully used to obtain high charges/energy storage (MPS) structure/capacitor instead of conventional insulator layer performed traditional methods. As a result, the observed important changes in electrical parameters with frequency and voltage depend on Nss, their t, Rs, organic interlayer, and interfacial or dipole polarization.
The electrical characteristic of an MIS structure with biocompatible minerals doped (Brushite+Monetite: PVC) interface layer
Microelectronic Engineering, Apr 1, 2022
Dielectric spectroscopy studies and ac electrical conductivity on (AuZn)/TiO2/p-GaAs(110) MIS structures
Philosophical Magazine, Sep 12, 2015
In this study, we investigated temperature and voltage dependence of dielectric properties and ac... more In this study, we investigated temperature and voltage dependence of dielectric properties and ac electrical conductivity (σac) of (AuZn)/TiO2/p-GaAs(110) metal–insulator–semiconductor structures in the temperature range of 80–290 K using the capacitance–voltage and conductance–voltage measurements at 1 MHz. The intersection/crossing behaviour of C–V plots at sufficiently high forward biases and the increase in σac with increasing temperature was attributed to the lack of sufficient number of enough free charge carriers at low temperatures. The values of the dielectric constant (ε′), dielectric loss (ε″), loss tangent , ac electrical conductivity (σac), the real and imaginary parts of electric modulus () were found to be strong functions of temperature and applied bias voltage. The Cole–Cole plots between have shown only one semicircle for each temperature. This indicates one of the relaxation processes was suppressed and this can be attributed to the surface polarization effect. On the other hand, plot has a peak for each temperature. The plots revealed two linear regions with different slopes for sufficiently high forward biases (0.0, 0.5, and 1.0 V) which correspond to low (80–200 K) and moderate/intermediate (230–290 K) temperatures. Thus, the values of activation energy (Ea) were obtained from the slope of these Arrhenius plots for two linear regions as 87.3 and 3.4 meV, respectively, at 1.0 V. On the other hand, Mott plots have only one linear region except for 260 and 290 K and Mott parameters were determined from these plots at 0.0, 0.5 and 1.0 V.
A comparative study on the electrical characteristics of Au/n-Si structures with anatase and rutile phase TiO2 interfacial insulator layer
Journal of Alloys and Compounds, Sep 1, 2010
TiO2 thin films were deposited on polycrystalline n-type Si substrate using DC magnetron sputteri... more TiO2 thin films were deposited on polycrystalline n-type Si substrate using DC magnetron sputtering system. To improve the crystal quality, thermal annealing (TA) process was done at 700°C and 900°C. The effect of TA on the structural properties was investigated using high resolution X-ray diffraction (HRXRD). It was observed that the phase transition from amorphous phase to anatase and rutile
Research Square (Research Square), Mar 18, 2021
A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact w... more A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact were prepared on the surface by the sputtering method and then their basic electrical features for example diffusion-potential (VD), doping density of donor-atoms (ND), Fermienergy (EF), barrier-height (ΦB), and depletion layer-width (WD) were extracted reverse-bias C - 2 -V plots as function frequency and voltage. The voltage profile of interface/surface-states (Nss)/ relaxation-times (τ), and series resistance (Rs) were also obtained from the admittance and Nicollian-Brews method, respectively. Strongly frequency-dependent and voltage especially in both accumulation and depletion regions due to the existence of Nss, Rs, and polarization as well as (NiS-doped PVP) organic interlayer. At low frequency, the observed higher value of C and G shows that thin (NiS:PVP) interlayer can be successfully used to obtain high charges/energy storage (MPS) structure/capacitor instead of conventional insulator layer performed traditional methods. As a result, the observed important changes in electrical parameters with frequency and voltage depend on Nss, their , Rs, organic interlayer, and interfacial or dipole polarization.
Effects of annealing and deposition temperature on the structural and optical properties of AZO thin films
Journal of Materials Science: Materials in Electronics, Nov 4, 2012
ABSTRACT Al-doped ZnO (AZO) thin films were deposited on p- type Si(100) substrate by r.f magnetr... more ABSTRACT Al-doped ZnO (AZO) thin films were deposited on p- type Si(100) substrate by r.f magnetron sputtering at 200, 300 and 400 °C substrate temperatures. The deposited films were annealed in air atmosphere for 1 h at temperatures of 700, 800 and 900 °C. The deposition temperature and post-deposition annealing effects on structural and optical properties of the AZO samples were analyzed using X-ray diffraction, atomic force microscope and photoluminescence (PL). After annealing, the value of full width half maximum of the diffraction peaks was decreased as well as, the intensity of visible and strong UV PL emission peaks were increased with temperature. However, the deep-level emission related with zinc point defects was removed by annealing of the samples. Results revealed that all of the as-deposited and annealed AZO films have hexagonal structure along (002) direction and their crystallinity were improved with the increased deposition and post-growth annealing temperatures. In addition, the surface roughness and the particle size of the films were increased with increased deposition and annealing temperatures.
Semiconductors, Oct 1, 2013
The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in A... more The aim of this study is to determine the reverse-bias leakage current conduction mechanisms in Au/SiO 2 /n-GaAs metal-insulator-semiconductor type Schottky contacts. Reverse-bias current-voltage measurements (I-V ) were performed at room temperature. The using of leakage current values in SiO 2 at electric fields of 1.46-3.53 MV/cm, ln(J/E) vs. √ E graph showed good linearity. From this plot, dielectric constant of SiO 2 was calculated as 3.7 and this value is perfect agreement with 3.9 which is value of SiO 2 dielectric constant. This indicates, Poole-Frenkel type emission mechanism is dominant in this field region. On the other hand, electric fields between 0.06-0.73 and 0.79-1.45 MV/cm, dominant leakage current mechanisms were found as ohmic type conduction and space charge limited conduction, respectively.
Politeknik dergisi, Jun 1, 2020
In this study, InGaN/GaN structures are grown by using Metal Organic Chemical Vapor Deposition (M... more In this study, InGaN/GaN structures are grown by using Metal Organic Chemical Vapor Deposition (MOCVD) technique. Some structural, optical and morphological properties of InGaN/GaN structures are investigated in detail. For structural analysis, X-ray diffraction (XRD), for optical, Raman and morphological, Atomic Force Microscopy (AFM) measurement techniques are used. In XRD analysis both samples presented hexagonal crystal structure. XRD peaks for these two samples showed small differences dependent on growth conditions. Strain and stress values are determined from XRD and they are compared with Raman results. In Raman analysis, five different chemicals are determined in both samples. Raman analysis results are in good accordance with XRD, growth conditions and AFM images. In AFM images, there can be seen hills and holes and they are partly homogeneous. There are also some white regions in AFM images. According to Raman peak center data, these white regions are detected as white rust.
Beyaz Led uygulamaları için InGaN LED yapılarınanalizi
Politeknik dergisi, 2017
Structural, morphological, optical and electrical properties of the Ti doped-ZnO (TZO) thin film prepared by RF sputter technique
Physica B-condensed Matter, Sep 1, 2021
Abstract In this study, the structural, morphological, optical, as well as electrical properties ... more Abstract In this study, the structural, morphological, optical, as well as electrical properties of the titanium doped (wt 5%) ZnO (TZO) thin film grown with the RF sputtering system was examined. TZO thin films were deposited on both corning glass (CG) and n–type Si substrates. It was determined that the TZO thin film deposited on CG has crystallinity, good surface homogeneity, low surface roughness as well as suitable band gap value from X–Ray diffraction (XRD), atomic force microscopy (AFM) as well as UV–Vis analysis. In addition, TZO thin film deposited on the n–Si substrate was used to determine the electrical properties. The current–voltage (I–V) measurements of the Au/TZO/n–Si structure was done at 80 K and 300 K. Capacitance–voltage ( C – V ) and conductance–voltage ( G / ω – V ) measurements of the Au/TZO/n–Si structure was examined for 0.3, 0.5 and 1 MHz.
Physica B-condensed Matter, Jun 1, 2007
The current-voltage (I-V) measurements on Al/ZnS Schottky barrier diodes in the temperature range... more The current-voltage (I-V) measurements on Al/ZnS Schottky barrier diodes in the temperature range 303 -423 K by the step of 15 K were carried out. The forward I-V characteristics were analyzed on the basis of the thermionic emission theory. The temperature dependence I-V parameters such as ideality factor (n) and barrier height ( b0 ) have been explained on the basis of inhomogeneity. An abnormal increase of apparent barrier height and decrease of ideality factor with increasing temperature have been explained due to the barrier height inhomogeneities on the basis of the thermionic emission theory with Gaussian distribution. Experimental results reveal the existence of a single Gaussian distribution with apparent barrier height value ( ) of 1.091 eV and standard deviations ( s ) of 0.18 V. Richardson constant (A*) was obtained as 8.49 x 10 -2 A.m -2 K -2 from the ln(I 0 /T 2 ) vs. q/kT plot, which is far from the calculated value of 5.6 x 10 5 A.m -2 K -2 . The modified Richardson plotof ln(I 0 /T 2 ) -(q 2 s 2 /2k 2 T 2 ) gives and A* values as 1.093 eV and 6.07 x 10 5 A.m -2 K -2 , without using the temperature coefficient of the barrier height. This obtained value of A* is extremely close to the previously calculated value. So, the temperature dependence of the forward bias I-V characteristics of the Schottky device can be successfully explained on the basis of the thermionic emission mechanism with a single Gaussian distribution of the barrier heights.
Optik, Sep 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Physica B-condensed Matter, Feb 1, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Au and non-Au based rare earth metal-silicide ohmic contacts to p-InGaAs
Solid-state Electronics, Jul 1, 2011
ABSTRACT The aim of this study is to improve the electrical properties of ohmic contacts that pla... more ABSTRACT The aim of this study is to improve the electrical properties of ohmic contacts that plays crucial role on the performance of optoelectronic devices such as laser diodes (LDs), light emitting diodes (LEDs) and photodetectors (PDs). The conventional (Pd/Ir/Au, Ti/Pt/Au and Pt/Ti/Pt/Au), Au and non-Au based rare earth metal-silicide ohmic contacts (Gd/Si/Ti/Au, Gd/Si/Pt/Au and Gd/Si/Pt) to p-InGaAs were investigated and compared each other. To calculate the specific contact resistivities the Transmission Line Model (TLM) was used. Minimum specific contact resistivity of the conventional contacts was found as 0.111 × 10−6 Ω cm2 for Pt/Ti/Pt/Au contact at 400 °C annealing temperature. For the rare earth metal-silicide ohmic contacts, the non-Au based Gd/Si/Pt has the minimum value of 4.410 × 10−6 Ω cm2 at 300 °C annealing temperature. As a result, non-Au based Gd/Si/Pt contact shows the best ohmic contact behavior at a relatively low annealing temperature among the rare earth metal-silicide ohmic contacts. Although the Au based conventional ohmic contacts are thermally stable and have lower noise in electronic circuits, by using the non-Au based rare earth metal-silicide ohmic contacts may overcome the problems of Au-based ohmic contacts such as higher cost, poorer reliability, weaker thermal stability, and the device degradation due to relatively higher alloying temperatures. To the best of our knowledge, the Au and non-Au based rare earth metal-silicide (GdSix) ohmic contacts to p-InGaAs have been proposed for the first time.
Journal of Applied Physics, Mar 12, 2014
Three InGaAs/InP structures for photodetector applications were grown with different indium compo... more Three InGaAs/InP structures for photodetector applications were grown with different indium compositions by MBE technique. The structural properties of the samples have been obtained by means of high resolution X-ray diffraction and secondary ion mass spectrometry measurements. Three InGaAs/InP metal-semiconductor-metal devices were fabricated at room temperature. The experimental forward and reverse bias current-voltage characteristics of the devices such as ideality factor, barrier height, and saturation current were evaluated considering the structural properties of the grown structures. The carrier recombination lifetime and diffusion length in the devices were also calculated using carrier density and mobility data obtained with Hall effect measurement at room temperature. It was determined that all room temperature fabricated devices improved the Schottky barrier height. Especially, the device fabricated on the lower mismatched structure exhibited barrier height enhancement from 0.2 eV, which is the conventional barrier height to 0.642 eV. In addition, the obtained results show that the room temperature fabricated devices on InGaAs/InP structures can be convenient for infrared photodetector applications.
SEMICONDUCTOR STRUCTURES, LOWDIMENSIONAL SYSTEMS, AND QUANTUM PHENOMENA The Analysis of Leakage Current in MIS Au/SiO 2 /nGaAs at Room Temperature 1
On the frequency-dependent complex-dielectric, complex-electric modulus and conductivity in Au/(NiS:PVP)/n-Si structures
Journal of Materials Science: Materials in Electronics, Jul 17, 2021
The values of complex-dielectric (ε* = ε′ − jε″), loss-tangent (tanδ), complex-electric modulus (... more The values of complex-dielectric (ε* = ε′ − jε″), loss-tangent (tanδ), complex-electric modulus (M* = M′ + jM″), and ac electrical-conductivity (σac) of the performed Au/(NiS:PVP)/n-Si structures were extracted from the measured impedance-spectroscopy method (ISM) in frequency range of 10 kHz–1 MHz and voltage ((− 2 V)–(+ 3 V)). These parameters, which constitute the main subject of our study, have been obtained from high frequency and voltage values, more particularly in the depletion and accumulation regions. The decrease of dielectric-constant (ε′), dielectric-loss (ε″), and tanδ with increasing frequency for almost every voltage were explained by Maxwell–Wagner type relaxation processes. The observed higher-values of ε′ and ε″ at low frequencies result from surface-states (Nss) and dipole-polarization. Since Nss has sufficient time to keep up with the applied voltage signal, dipoles can respond to the electric field to reorient themselves. An increase in M′ values was observed at increasing frequency values attributed to the long-distance mobility of the carriers. On the other hand, the observed peak in the M″ − ln (f) curves was attributed to a distinctive distribution of Nss located at Au/(NiS:PVP) interface depend on their lifetime. The obtained value of ε′ even at 10 kHz at 3 V is indicated that the used (NiS:PVP) organic-interlayer can be used a superior alternative instead of SiO2 or SnO2 which are conventional interlayers thanks to its low-cost, flexibility, easy production techniques such as spin-coating or electro-spinning technique at room condition, successfully.
Analysis of temperature dependent electrical characteristics of Au/n-GaAs/GaAs structures in a wide temperature range
Vacuum, Sep 1, 2008
The temperature dependence of some electrical parameters of Au/n-GaAs/GaAs structures obtained fr... more The temperature dependence of some electrical parameters of Au/n-GaAs/GaAs structures obtained from the forward bias current–voltage (I–V) and reverse bias capacitance–voltage (C–V) characteristics is studied in the temperature range of 79–400K. The forward bias current I is found to be proportional to Io(T)exp(AV), where A is the slope of Ln(I)–V curves and almost independent of the voltage and temperature, and
Determination of surface morphology and electrical properties of MoO3 layer deposited on GaAs substrate with RF magnetron sputtering
Journal of Materials Science: Materials in Electronics, Apr 9, 2021
We report the effects of the substrate temperature on the surface morphology of Molybdenum tri-ox... more We report the effects of the substrate temperature on the surface morphology of Molybdenum tri-oxide (MoO3) thin films and the electrically detailed examination of Au/MoO3/n–GaAs MOS heterojunction structure with the best homogeneity. MoO3 thin film was deposited both on soda–lime silicate glass as a thin film and n-type and (100) oriented GaAs substrates using RF magnetron sputtering method at substrate temperatures of room temperature, 100 °C, 200 °C and 300 °C. Surface morphology of the MoO3 thin films were investigated by utilizing atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements. AFM and SEM results have shown that MoO3 thin film with substrate temperature of 200 °C has the lowest surface roughness and the homogeneity of the film structures significantly enhances with increasing substrate temperature up to 200 °C. An inclement in roughness of thin film structure was detected at higher temperature than 200 °C due to the deterioration of homogeneity. Therefore, we primarily focused on the MoO3 thin films produced at the substrate temperature of 200 °C to examine the electrical properties of Au/MoO3/n–GaAs MOS heterojunction device. In order to determine the electrical properties, temperature dependent I-V\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I-V$$\end{document} measurements were performed in between 200 and 400 K by steps of 25 K. The fundamental electrical parameters such as saturation current (I0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${I}_{0}$$\end{document}), ideality factor (n\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$n$$\end{document}), and barrier height (ϕ0\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\phi }_{0}$$\end{document}) were calculated by analyzing the forward bias I-V\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I{-}V$$\end{document} curves at different temperatures. The series resistance (Rs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{s}$$\end{document}) values of the device were also determined using the plot of structure resistance (Ri\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{\text{i}}$$\end{document}) vs applied bias voltage (Vi\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${V}_{i}$$\end{document}), Thermionic Emission Theory and Cheung and Cheung methods. The Rs\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${R}_{s}$$\end{document} value of Au/MoO3/n–GaAs MOS heterojunction device shows an abnormal behavior of up to 350 K, which is the critical temperature value and tends to increase with increasing temperature. Above the critical temperature value, it exhibits ideal behavior.
Temperature dependence of electrical characteristics and interface state densities of Au/n-type Si structures with SnS doped PVC interface
Physica Scripta, Aug 24, 2022
Frequency and voltage-dependent electrical parameters, interface traps, and series resistance profile of Au/(NiS:PVP)/n-Si structures
Journal of Materials Science: Materials in Electronics, May 1, 2021
A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact w... more A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact were prepared on the surface by the sputtering method and then their basic electrical features for example diffusion-potential (VD), doping density of donor-atoms (ND), Fermi-energy (EF), barrier-height (ΦB), and depletion layer-width (WD) were extracted reverse-bias C-2-V plots as function frequency and voltage. The voltage profile of interface/surface-states (Nss)/ relaxation-times (τ), and series resistance (Rs) were also obtained from the admittance and Nicollian-Brews method, respectively. Strongly frequency-dependent and voltage especially in both accumulation and depletion regions due to the existence of Nss, Rs, and polarization as well as (NiS-doped PVP) organic interlayer. At low frequency, the observed higher value of C and G shows that thin (NiS:PVP) interlayer can be successfully used to obtain high charges/energy storage (MPS) structure/capacitor instead of conventional insulator layer performed traditional methods. As a result, the observed important changes in electrical parameters with frequency and voltage depend on Nss, their t, Rs, organic interlayer, and interfacial or dipole polarization.
The electrical characteristic of an MIS structure with biocompatible minerals doped (Brushite+Monetite: PVC) interface layer
Microelectronic Engineering, Apr 1, 2022
Dielectric spectroscopy studies and ac electrical conductivity on (AuZn)/TiO2/p-GaAs(110) MIS structures
Philosophical Magazine, Sep 12, 2015
In this study, we investigated temperature and voltage dependence of dielectric properties and ac... more In this study, we investigated temperature and voltage dependence of dielectric properties and ac electrical conductivity (σac) of (AuZn)/TiO2/p-GaAs(110) metal–insulator–semiconductor structures in the temperature range of 80–290 K using the capacitance–voltage and conductance–voltage measurements at 1 MHz. The intersection/crossing behaviour of C–V plots at sufficiently high forward biases and the increase in σac with increasing temperature was attributed to the lack of sufficient number of enough free charge carriers at low temperatures. The values of the dielectric constant (ε′), dielectric loss (ε″), loss tangent , ac electrical conductivity (σac), the real and imaginary parts of electric modulus () were found to be strong functions of temperature and applied bias voltage. The Cole–Cole plots between have shown only one semicircle for each temperature. This indicates one of the relaxation processes was suppressed and this can be attributed to the surface polarization effect. On the other hand, plot has a peak for each temperature. The plots revealed two linear regions with different slopes for sufficiently high forward biases (0.0, 0.5, and 1.0 V) which correspond to low (80–200 K) and moderate/intermediate (230–290 K) temperatures. Thus, the values of activation energy (Ea) were obtained from the slope of these Arrhenius plots for two linear regions as 87.3 and 3.4 meV, respectively, at 1.0 V. On the other hand, Mott plots have only one linear region except for 260 and 290 K and Mott parameters were determined from these plots at 0.0, 0.5 and 1.0 V.
A comparative study on the electrical characteristics of Au/n-Si structures with anatase and rutile phase TiO2 interfacial insulator layer
Journal of Alloys and Compounds, Sep 1, 2010
TiO2 thin films were deposited on polycrystalline n-type Si substrate using DC magnetron sputteri... more TiO2 thin films were deposited on polycrystalline n-type Si substrate using DC magnetron sputtering system. To improve the crystal quality, thermal annealing (TA) process was done at 700°C and 900°C. The effect of TA on the structural properties was investigated using high resolution X-ray diffraction (HRXRD). It was observed that the phase transition from amorphous phase to anatase and rutile
Research Square (Research Square), Mar 18, 2021
A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact w... more A thin (NiS-doped PVP) interface layer was spin-coated on n-Si substrate and between Au contact were prepared on the surface by the sputtering method and then their basic electrical features for example diffusion-potential (VD), doping density of donor-atoms (ND), Fermienergy (EF), barrier-height (ΦB), and depletion layer-width (WD) were extracted reverse-bias C - 2 -V plots as function frequency and voltage. The voltage profile of interface/surface-states (Nss)/ relaxation-times (τ), and series resistance (Rs) were also obtained from the admittance and Nicollian-Brews method, respectively. Strongly frequency-dependent and voltage especially in both accumulation and depletion regions due to the existence of Nss, Rs, and polarization as well as (NiS-doped PVP) organic interlayer. At low frequency, the observed higher value of C and G shows that thin (NiS:PVP) interlayer can be successfully used to obtain high charges/energy storage (MPS) structure/capacitor instead of conventional insulator layer performed traditional methods. As a result, the observed important changes in electrical parameters with frequency and voltage depend on Nss, their , Rs, organic interlayer, and interfacial or dipole polarization.
Effects of annealing and deposition temperature on the structural and optical properties of AZO thin films
Journal of Materials Science: Materials in Electronics, Nov 4, 2012
ABSTRACT Al-doped ZnO (AZO) thin films were deposited on p- type Si(100) substrate by r.f magnetr... more ABSTRACT Al-doped ZnO (AZO) thin films were deposited on p- type Si(100) substrate by r.f magnetron sputtering at 200, 300 and 400 °C substrate temperatures. The deposited films were annealed in air atmosphere for 1 h at temperatures of 700, 800 and 900 °C. The deposition temperature and post-deposition annealing effects on structural and optical properties of the AZO samples were analyzed using X-ray diffraction, atomic force microscope and photoluminescence (PL). After annealing, the value of full width half maximum of the diffraction peaks was decreased as well as, the intensity of visible and strong UV PL emission peaks were increased with temperature. However, the deep-level emission related with zinc point defects was removed by annealing of the samples. Results revealed that all of the as-deposited and annealed AZO films have hexagonal structure along (002) direction and their crystallinity were improved with the increased deposition and post-growth annealing temperatures. In addition, the surface roughness and the particle size of the films were increased with increased deposition and annealing temperatures.