Fabrication and characterization of n-IZO/p-Si and p-ZnO:(In, N)/n-Si thin film hetero-junctions by dc magnetron sputtering (original) (raw)

I-V characteristics of n-ZnO∕poly-Si thin film heterostructure

2010

ZnO has been extensively studied for many different applications, such as gas sensors, transparent conductive electrodes in solar cells and light emitting diodes, etc., because of its chemical stability and sensitivity to different adsorbed gases, amenability to doping, large energy gap, nontoxicity and low cost. ZnO thin films have been applied for device engineering in different heterostructures, as well. In this work the I-V characteristics of two thin film heterostructures n-ZnO/p-poly-Si with ZnO films with different thicknesses, 80 and 300 nm are studied. The ZnO polycrystalline films are deposited by RF sputtering in an atmosphere of Ar on the surface of a p-type poly-Si layer. The poly-Si films are prepared on glass substrate by the method of Aluminum Induced Crystallization (AIC) from precursor layers of Al and a-Si:H. The Al and a-Si:H precursor films are deposited by magnetron sputtering on glass substrate. The a-Si:H film precursors contain 9 at.% hydrogen. The isotermal annealing of the structure glass/Al/a-Si:H is performed in forming gas (N 2 +5%H 2) in the temperature range of 530 0 C-550 o C for 7 and 21 h. The properties of the films are studied by X-Ray Diffraction (XRD), optical microscopy, optical transmission and reflection, and Raman spectrioscopy. The I-V characteristics of the thin films heterostructures n-ZnO/ poly-Si show diode behaviour and ideality factor of 2.2 and 3.5. The structures exhibit photosensitivity under illumination.

Annealing Effects on Electrical and Optical Properties of N-ZnO/P-Si Heterojunction Diodes

Advanced Materials Research, 2011

The effects of post fabrication annealing on the electrical characteristics of n-ZnO/p-Si heterostructure are studied. The nanorods of ZnO are grown by aquous chemical growth (ACG) technique on p-Si substrate and ohmic contacts of Al/Pt and Al are made on ZnO and Si. The devices are annealed at 400 and 600 o C in air, oxygen and nitrogen ambient. The structural and electrical characteristics are studied by scanning electron microscopy (SEM), photoluminescence (PL), current -voltage (I-V) and capacitance -voltage (C-V) measurements. PL spectra indicated higher ultraviolet (UV) to visible emission ratio with a strong peak of near band edge emission (NBE) centered from 375-380 nm and very weak broad deep-level emissions (DLE) centered from 510-580 nm. All diodes show typical rectifying behavior as characterized by I-V measurements. The barrier heights are found to increase with annealing temperatures in air and oxygen and decrease in nitrogen ambient. The results indicated that annealing in air and oxygen resulted in a decrease in the reverse current and increase in the barrier height repairing low barrier leakage which may be present due to the barrier inhomogenieties at the interface.

Nanostructure, optical and electrical properties of p-NiO/n-Si heterojunction diodes

Applied Physics A, 2020

Evolutions on structural, morphological, optical and electrical characteristics of Pt/p-NiO/n-Si/Al thin-film heterojunction diodes before and after various thermal annealing temperatures have been investigated in details. Increases in the annealing temperature improve the crystalline structures of the films, i.e., stress on the film decreases and grain size of the film increases after annealing. The surface roughness of the films enhances from 3.60 to 4.59 nm, especially after 600 °C annealing. This rise in the surface roughness is possible due to the increase in the grain size of the films which causes swelling effect after high-temperature annealing. The energy band gap of the NiO films changes from 3.43 eV to 3.34 eV after annealing temperature up to 450 °C, while it slightly increases after 600 °C annealing process. These observed variations on the band gap values are due to the changes on the crystalline, microstructure and interfacial parameters of the films. On the other hand, the surface modifications also affect the electrical characteristics of the heterojunction diodes. The lowest sheet resistance is obtained to be 65.2 Ω/sq after 450 °C annealing process. Reverse saturation current increases up to 34.1 nA and barrier height also decreases from 0.82 eV to 0.75 eV depending on the annealing temperature. In addition, the lowest value of the ideality factor is obtained to be 1.51 for the diodes annealed at 450 °C. It can be concluded that the annealing-induced surface modifications significantly affect the electrical performance of the diodes and the optimum annealing temperature is 450 °C for the heterojunction diode applications of the p-NiO/n-Si films.

DIODE PROPERTY OF n-ZnO/p-Si HETEROJUNCTION STRUCTURE IN THE DARK AND ILLUMINATION CONDITION

Selçuk-Teknik Dergisi, 2018

In this study, Zinc Oxide (ZnO) thin film was deposited on the Silicon (Si) wafer by Pulsed Laser Deposition (PLD) to form n-ZnO/p-Si heterojunction. The morphological and the crystal structure of ZnO thin film was analysed and interpreted by Atomic Force Microscopy (AFM) and X-Ray Diffraction (XRD), respectively. The absorption spectrum was obtained by using the UV-Vis spectra and the band gap (Eg) was found by using Tauc Law. The current density-Voltage (J-V) plot was obtained at room temperature (RT) in the dark and under illumination. The barrier height (BH) and ideality factor were found about 0.46 eV and 1.35, respectively. The largest values of open circuit voltage (Voc) and short-circuit current (Jsc) were about 100 mV and 3×10-2 mA/cm 2 , respectively. It has been measured that ZnO/Si heterojunction diode behaves a solar cell like device under the illumination conditions.

Effect of Deposition Temperature on the Physical Performance of n-ZnO/p-Si Heterojunction

JOURNAL OF EDUCATION AND SCIENCE

Comparative study of the physical characteristics of n-ZnO/p-Si heterojunction diode has been done as a function of deposition temperature in the range of 300-600 °C. Transparent conducting (TC) Zinc Oxide (ZnO) thin films were deposited by atmospheric pressure chemical vapor deposition (APCVD) technique on the p-Si(100) and glass substrates. Also, the influences of different deposition temperature on the morphology and optical properties of ZnO films were studied. Both the average surface roughness (from 62.8 to 18.8 nm) and the root mean square (from 78.2 to 24 nm) of ZnO films were decreased with the increase in the deposition temperature. Optical transmittance measurement results exhibited good transparency within the visible wavelength range for the films prepared at a temperature above 400 C. The current-voltage (I-V) characteristics of the heterojunction diodes exhibited rectification behavior and depend on the deposition temperature. The electrical parameters of the n-ZnO/p-Si heterojunctions were also affected by the deposition temperature. The diodes prepared at a temperature above 400 C were possessed lower reverse saturation current and high rectification ratio compared to those fabricated at a relatively lower temperature such as 300 C or 400 °C. Such low a temperature grown n-ZnO/p-Si heterojunction diodes with lower reverse saturation current could be suitable for photo-detection applications.

Analysis of IV Characteristics of Pd/ZnO Thin Film/n-Si Schottky Diodes with Series Resistance

Journal of Nanoelectronics and Optoelectronics, 2014

The measured current-voltage characteristics have been analyzed by using conventional thermionic emission model, Cheung's method and Norde's technique to estimate the barrier height, ideality factor and series resistance of the vertical Pd/n-ZnO thin film Schottky contacts grown on n-Si substrates by thermal evaporation method. While the conventional analysis gives barrier height ∼ 0.67 eV, ideality factor ∼ 2.36 and series resistance ∼ 5333 , the Cheung's method has resulted in nearly same barrier height ∼ 0.67 eV but a much larger value of ideality factor ∼ 5.29 and a relatively smaller value of series resistance ∼ 4734 . The Norde's method results in nearly a same value of barrier height ∼ 0.67 eV but a much larger value of barrier height ∼ 30 983 × 10 3 than the other two approaches. The study shows that Cheung's method could be the best and most practical for estimating the diode parameters including the effect of series resistance of the Pd/n-ZnO thin film/n-Si Schottky diode structures under consideration.

Analysis of I–V Characteristics of Pd/ZnO Thin Film/n-Si Schottky Diodes with Series Resistance

Journal of Nanoelectronics and Optoelectronics

The measured current–voltage characteristics have been analyzed by using conventional thermionic emission model, Cheung’s method and Norde’s technique to estimate the barrier height, ideality factor and series resistance of the vertical Pd/n-ZnO thin film Schottky contacts grown on n-Si substrates by thermal evaporation method. While the conventional analysis gives barrier height 0.67 eV, ideality factor 2.36 and series resistance 5333 �, the Cheung’s method has resulted in nearly same barrier height 0.67 eV but a much larger value of ideality factor 5.29 and a relatively smaller value of series resistance 4734 �. The Norde’s method results in nearly a same value of barrier height 0.67 eV but a much larger value of barrier height 30�983×103 � than the other two approaches. The study shows that Cheung’s method could be the best and most practical for estimating the diode parameters including the effect of series resistance of the Pd/n-ZnO thin film/n-Si Schottky diode structures unde...

Fabrication and characterization of p-Si/n-ZnO heterostructured junctions

Microelectronics Journal, 2009

In this paper ZnO nanorods and nanodots (with and without a SiO 2 buffer layer) were grown on p-Si, forming p-n heterojunctions. The nanorod devices showed no visible electroluminescence (EL) emission but showed rectifying behavior. Covering around 60% of the length of the nanorods with PMMA produced an ideality factor of 3:91 AE 0:11 together with a reverse saturation current of 6:53 AE 4:2 Â 10 À8 A. Up to two orders of magnitude rectification was observed for the current at bias À3 and 3 V. The nanodot devices showed EL emission under forward bias conditions. It seems that the buffer layer increased both the stability and efficiency of the devices, since the buffer layer device could operate at larger applied voltage and showed EL emission under reverse bias.

Influence of post-deposition annealing on structural, optical and electrical characteristics of NiO/ZnO thin film hetero-junction

MRS Proceedings, 2012

ABSTRACTTransparent p-n hetero-junction diodes are fabricated using, p-type NiO and n-type ZnO thin films deposited onto a Pt/Ti/glass substrate utilizing RF sputtering technique. The prepared hetero-junctions are studied for the structural, electrical and optical properties and the effect of post-deposition annealing is investigated through I-V measurements and XRD analysis. The as deposited hetero-junction is found to be giving ohmic behaviour while with post-annealing treatment it result in rectification with a ratio of forward-to-reverse current as high as 15 in the range -1.0 to 1.0 V. Forward threshold and the reverse breakdown voltages are found to be about 0.5 and -2.7 V, respectively. The forward-bias I-V characteristics are dominated by the flow of space-charge-limited current with an optical transmission of above 50 % in the visible region important for the transparent electronic device fabrication.