Electrical Properties of p-Si/n-ZnO Nanowires Heterojunction Devices (original) (raw)
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IEEE Transactions on Nanotechnology, 2000
This paper presents the electrical characteristics of n-zinc oxide (ZnO) nanowires (NWs)/p-Si (100) heterojunction diodes fabricated by the oxidation of thermally deposited metallic Zn on Al:ZnO-coated p-Si 1 0 0 substrates. The electrical parameters of the n-ZnO NWs/p-Si diodes have been estimated by using the room temperature capacitance-voltage (C-V) and temperature-dependent current-voltage (I-V) characteristics of the heterojunction. The carrier concentration of the ZnO NW film and the barrier height of the diode estimated from the C-V characteristics at room temperature are 1.54 × 10 15 cm −3 and 0.75 eV, respectively. The thermionic emission model was used to analyze the temperature-dependent measured I-V characteristics to estimate the parameters of the diode. The estimated values of the barrier height and ideality factor at room temperature were 0.715 eV and 2.13, respectively. The spatial barrier inhomogeneity was included in the aforementioned analysis by assuming a Gaussian distribution for the barrier height at the n-ZnO NWs/p-Si heterojunction. The Richardson constant A * of ZnO was found to be increased from a relatively low value of 9.75 × 10 −8 A · cm −2 · K −2 to a more realistic value of 49A · cm −2 · K −2 after incorporating the barrier inhomogeneity phenomenon in the aforementioned analysis.
A p-silicon nanowire/n-ZnO thin film heterojunction diode prepared by thermal evaporation
Journal of Semiconductors, 2014
This paper represents the electrical and optical characteristics of a SiNW/ZnO heterojunction diode and subsequent studies on the photodetection properties of the diode in the ultraviolet (UV) wavelength region. In this work, silicon nanowire arrays were prepared on p-type (100)-oriented Si substrate by an electroless metal deposition and etching method with the help of ultrasonication. After that, catalyst-free deposition of zinc oxide (ZnO) nanowires on a silicon nanowire (SiNW) array substrate was done by utilizing a simple and cost-effective thermal evaporation technique without using a buffer layer. The SEM and XRD techniques are used to show the quality of the as-grown ZnO nanowire film. The junction properties of the diode are evaluated by measuring current-voltage and capacitance-voltage characteristics. The diode has a well-defined rectifying behavior with a rectification ratio of 190 at˙2 V, turn-on voltage of 0.5 V, and barrier height is 0.727 eV at room temperature under dark conditions. The photodetection parameters of the diode are investigated in the bias voltage range of˙2 V. The diode shows responsivity of 0.8 A/W at a bias voltage of 2 V under UV illumination (wavelength D 365 nm). The characteristics of the device indicate that it can be used for UV detection applications in nano-optoelectronic and photonic devices.
Behavior of n-ZnO nanorods/p-Si heterojunction devices at higher temperatures
This work explores the temperature dependent heterojunction behavior of n-type zinc oxide ZnO nanorods/ZnO/ p-Si diodes. The as-grown ZnO nanorod structures on ZnO coated p-Si substrates are single crystalline and grown along the 001 direction. The p-n diode showed an excellent stability over the temperature range of 20–150 °C due to highly doped p-type Si substrate. The turn-on and breakdown voltage of the device slightly decreased with an increase of temperature whereas the saturation current of the device increased from 0.42 to 0.67 A. The device behavior at different temperatures in forward as well as reverse biased conditions are studied and reported.
Electrical Characterization of Si/ZnO Nanorod PN Heterojunction Diode
e electrical characterization of p-Silicon (Si) and n-Zinc oxide (ZnO) nanorod heterojunction diode has been performed. ZnO nanorods were grown on p-Silicon substrate by the aqueous chemical growth (ACG) method. e SEM image revealed high density, vertically aligned hexagonal ZnO nanorods with an average height of about 1.2 μm. Electrical characterization of n-ZnO nanorods/p-Si heterojunction diode was done by current-voltage (I-V), capacitance-voltage (C-V), and conductance-voltage (G-V) measurements at room temperature. e heterojunction exhibited good electrical characteristics with diode-like rectifying behaviour with an ideality factor of 2.7, rectification factor of 52, and barrier height of 0.7 V. Energy band (EB) structure has been studied to investigate the factors responsible for small rectification factor. In order to investigate nonidealities, series resistance and distribution of interface state density (N SS) below the conduction band (CB) were extracted with the help of I-V and C-V and G-V measurements. e series resistances were found to be 0.70, 0.73, and 0.75 KΩ, and density distribution interface states from 8.38 × 10 12 to 5.83 × 10 11 eV −1 cm −2 were obtained from 0.01 eV to 0.55 eV below the conduction band.
Open Physics
The effect of post-growth annealing treatment of zinc oxide (ZnO) nanorods on the electrical properties of their heterojunction diodes (HJDs) is investigated. ZnO nanorods are synthesized by the low-temperature aqueous solution growth technique and annealed at temperatures of 400 and 600°C. The as-grown and annealed nanorods are studied by scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. Electrical characterization of the ZnO/Si heterojunction diode is done by current–voltage (I–V) and capacitance–voltage (C–V) measurements at room temperature. The barrier height (ϕ B), ideality factor (n), doping concentration and density of interface states (N SS) are extracted. All HJDs exhibited a nonlinear behavior with rectification factors of 23, 1,596 and 309 at ±5 V for the as-grown, 400 and 600°C-annealed nanorod HJDs, respectively. Barrier heights of 0.81 and 0.63 V are obtained for HJDs of 400 and 600°C-annealed nanorods, respectively. The energy distribution o...
Growth and Properties of Sn-Doped ZnO Nanowires for Heterojunction Diode Application
Science of Advanced Materials, 2014
Well-crystalline Sn-doped ZnO nanowires were grown on p-type silicon substrates by simple non-catalytic thermal evaporation process. The prepared nanowires were examined in terms of their morphological, compositional and structural properties which revealed that the as-grown nanowires are well-crystalline Sn-doped ZnO, possessing wurtzite hexagonal phase structure and grown in very high density over whole silicon substrate. Further, the as-grown n-Sn-doped ZnO nanowires were used to fabricate n-Sn-ZnO/p-Si heterojunction diode. Temperature dependant electrical properties (294-353 K and 373-433 K) of the fabricated heterojunction diode were studied in the forward and reverse bias conditions and presented in this paper. The current-voltage characteristics at varying temperature of the heterojunction diode reveal that both the quality factor and Schottky barrier height depend on temperature. However, the mean barrier height is estimated ∼1.2 eV in one attempt of analysis when a Gaussian distribution of low barrier heights is considered and found almost ∼1 eV in another attempt when the Richardson plot is linearized. Furthermore, effective barrier heights of 0.55-0.75 eV are extracted in the temperature range 294-433 K when Tung model is used. These correspond to barrier heights of 0.93-0.35 eV extracted from C-V analysis in the same range of temperatures. Although the latter results from C-V analysis exhibit closer correlation with the Schottky barrier heights extracted from I-V analysis but the discrepancy between them still exist.
Materials Express
In this paper, the heterojunction diode based on n-Ga doped ZnO nanowires interconnected with disks/p-Si assembly was fabricated and their low-temperature electrical properties were examined. The Ga-doped ZnO nanowires interconnected with disks were grown over p-Si substrate and studied by numerous techniques to understand the structural, compositional and morphological characteristics. Electrical properties, at lowtemperatures ranging from 77 K–295 K, were examined for the fabricated heterojunction diode assembly both in reverse and forward biased conditions which exhibited an excellent stability over all the temperature range. The detailed electrical characterizations revealed that the current decreases gradually from 1.9 μA, to 0.87 μA to 0.84 μA when temperature increases from 77 K, 100 K to 150 K and then increases gradually from 1.86 μA–3.36 μA and to 9.95 μA when temperature increases from 200 K–250 K and to 295 K, respectively. Both the highest rectifying ratio at 100 K and ...
Effect of Annealing Atmosphere on the Diode Behaviour of ZnO/Si Heterojunction
Elektronika ir Elektrotechnika, 2021
The effect of thermal annealing atmosphere on the electrical characteristics of Zinc oxide (ZnO) nanorods/p-Silicon (Si) diodes is investigated. ZnO nanorods are grown by low-temperature aqueous solution growth method and annealed in Nitrogen and Oxygen atmosphere. As-grown and annealed nanorods are studied by scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. Electrical characteristics of ZnO/Si heterojunction diodes are studied by current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Improvements in rectifying behaviour, ideality factor, carrier concentration, and series resistance are observed after annealing. The ideality factor of 4.4 for as-grown improved to 3.8 and for Nitrogen and Oxygen annealed improved to 3.5 nanorods diodes. The series resistances decreased from 1.6 to 1.8 times after annealing. An overall improved behaviour is observed for oxygen annealed heterojunction diodes. The study suggests that by controlli...
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.
Beilstein journal of nanotechnology, 2014
A low cost, highly rectifying, nano heterojunction (p-ZnO/n-Si) diode was fabricated using solution-processed, p-type, ZnO nanoparticles and an n-type Si substrate. p-type ZnO nanoparticles were synthesized using a chemical synthesis route and characterized by XRD and a Hall effect measurement system. The device was fabricated by forming thin film of synthesized p-ZnO nanoparticles on an n-Si substrate using a dip coating technique. The device was then characterized by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The effect of UV illumination on the I-V characteristics was also explored and indicated the formation of a highly rectifying, nano heterojunction with a rectification ratio of 101 at 3 V, which increased nearly 2.5 times (232 at 3 V) under UV illumination. However, the cut-in voltage decreases from 1.5 V to 0.9 V under UV illumination. The fabricated device could be used in switches, rectifiers, clipper and clamper circuits, BJTs, MOSFETs and other ele...