Papers by Keyword: I-V Characteristics

Abstract: In this present work, Pristine and 10 at.% of In-doped ZrO₂thin films were deposited by spray pyrolysis technique at optimized substrate temperature [Ts=450°C]. The greater the proportion of Indium ion dopant, significantly influences the structural, optical, morphological, and electrical properties of deposit thin films. The deposited thin films were characterized with XRD, UV-Vis, PL, HR-TEM with EDAX, and I-V characterization Studies. The crystallinity of Zirconium dioxide thin film was improved and size of crystals were decreased by Indium ion substitution. Optical study revealed that the film's optical transmittance enhanced from 80.3 percent to 86.5% as a result of the dopant. The energy bandgap increased at 4.93eV - 4.57eV, systematically. HR-TEM studies show the homogeneous particle distribution and denser surface texture at 22nm and 19nm of average particle agglomerations. The study of PL emission shows an increase in intensity on the blue emission band with enriched crystalline quality. The conductivity of the ZrO₂ was higher affected by Indium ion may result in increased conductivity, with low resistivity property.

Abstract: The growth of vertically aligned ZnO Nanorods arrays using Zinc Nitrate hexahydrate and Hexamethylene Tetramine (HMTA), by Chemical Bath Deposition on Silicon Wafer was investigated. The growth is conducted under influence of Ethane-1,2-diamine, the amine based enhancer was evaluated based on three different ratios (1:0.5, 1:1, 1:1.5) of enhancer to the precursor (Zinc Nitrate and HMTA). The effect different ratios of enhancers on morphology aspect ratio and crystallinity of the as grown Nanorods were studied under Scanning electron microscope (SEM) and X-ray powder diffraction (XRD). Electrical Properties such as current–voltage characteristics were investigated, its correlation to the morphology and aspect ratio of the Nanorods in the presence of 100μL-500μL of Aromatic Compound Cyclohexane and at different applied voltages.

Abstract: The ZnSe/Si heterojunction is of specific interest since this structure provides effective solar cell and enables the integration of wide bandgap device in silicon circuits. It is known that the quality of the diode and the current transport mechanisms across the heterojunction may be greatly influenced by the quality of the interface and depends on the crystallinity of the film layer. In this work, n-ZnSe/p-Si (100) heterojunction was fabricated by thermal evaporating ZnSe thin films on p-Si (100) substrates. The current-voltage characteristics of n-ZnSe/p-Si (100) heterojunction were investigated in temperature range 20-300 K. Some important parameters such as barrier height, ideality factor and series resistance values evaluated by using thermionic emission (TE) theory and Cheung’s method at room temperature are n = 2.910, φ_B0 = 0.832 eV and 8.5910³ Ω, respectively. The temperature dependence of the saturation current and ideality factor are well described by tunneling enhanced recombination at junction interface with activation energy and characteristic energy values about 1.293 eV and E₀₀ = 95 meV, respectively. The carrier concentration of ZnSe thin films about 3.16×10¹³ cm^-3 was deduced from the C-V measurements at room temperature. Admittance spectroscopy was employed for analysis of the defect energy levels situated in depletion region. The results showed that there was a single trap level whose position in the band gap was close to 0.04 eV above valence band. The results of this work may be useful for application such as heterojunction solar cells.

Abstract: The lack of the high temperature I-V model greatly restricts the application of GaN HEMT devices. In this paper, the characteristic variation of GaN HEMT device under high temperature condition is investigated, and an improved I-V characteristics model of GaN HEMT transistors over a wide temperature range from 25°C to 300°C is proposed based on the classic Statz model. The experimental results indicate that the improved spice model, by taking the self-heating effect into account, is more accurate compared to the original Statz model. The proposed I-V model should be an available tool for the simulation of GaN HEMT device in designing integrated circuits at high temperature.

Abstract: The hetero p-n junctions of LBMO/ZnO were fabricated by ion beam sputtering. The sample shows clear temperature-dependent rectifying current (I)-voltage (V) characteristics, and junction resistance vs temperature curve is reflected by the CMR nature based on DEC model. The sample shows two-step switching, then the I-V is composed of very-low-resistance (VLR), low-resistance (LR) and high-resistance (HR) regions. The whole I-V behavior is changed by measurement running current. The switching is caused by the spot current, and the original VLR is restored when the current is reduced. The mechanism of switching is proposed in terms of the percolation paths composed of metallic FM-grains. Photo illumination effect on the I-V was investigated. The currents are increased in VLR and HR regions by the illumination. Two origins are possible, electronic process due to hole injection, and phase process. The percolation path might be reinforced by the light.

Abstract: In this paper, p-CuO/n-CdS heterojunction was prepared by thermal evaporating CdS thin films on CuO 1 mm thick ceramic pellet substrate. The electrical properties of p-CuO/n-CdS heterojunction were investigated by forward current–voltage–temperature (I–V–T) characteristics in the temperature range of 100-300 K. The junction barrier height, ideality factor, and the series resistance values of the diode evaluated by using thermionic emission (TE) theory and Cheung’s method are 0.566 eV, 5.535 and 618.24 Ω at 300 K, respectively. The junction barrier height, ideality factor and series resistance were found to be strong temperature dependence. In part of C-V measurements at room temperature, the obtained built-in potential value being 0.538 V is well consistent with the junction barrier height value evaluated from I-V measurements

Abstract: Single layer of titanium dioxide (TiO₂) is common metal oxide in fabricating memristor device. In this study, two types of memristor with composite metal oxide thin films will be demonstrated. The two types of memristor are titanium dioxide (TiO₂) thin film coated on zinc oxide (ZnO) thin film and ZnO coated on TiO₂ thin film. Sol-gel spin coating method was to coat metal oxide thin film and sputtering method for depositing the metal contact. Platinum (Pt) was selected as the top electrode and indium tin oxide (ITO) as the bottom electrode. The electrical characteristics were defined by performing I-V measurement using two point probe equipment. I-V characteristics showed shape of pinched hysteresis loop for both samples. Sample with TiO₂ coated on ZnO has slightly higher R_off/R_on ratio than sample ZnO coated on TiO₂ which means it more memristive than another one. The cross-section of sample with TiO₂ coated on ZnO had been performed as well by using Field-Emission Scanning Electron Microscopy (FESEM).

Abstract: Organic transistors consist of a vertical type are promising due to their shorter channel length. We have fabricated a vertical structure thin film phototransistor: ITO/CuPc/Al/CuPc/Cu. Detected this device and then the results show that the I-V properties of the transistors exhibit unsaturated characteristics and photosensitive characteristics. When V_ec=3V, amplification factor of the device without light is 16.5 and the 625nm light amplification factor is 266.2.

Abstract: In this work, n-CdS/p-CuFeO₂ heterojunction diode was fabricated by thermal evaporating CdS thin films on 1 mm thick-CuFeO₂ ceramic substrate with substrate temperature kept at 373 K during evaporation process. The forward current-voltage characteristics of n-CdS/p-CuFeO₂ heterojunction in a temperature range of 100-300 K were investigated to determine the electrical parameters and conduction mechanism. It was found that, at forward bias below 0.5 V, the conduction mechanism of the diode is dominated by thermionic emission (TE) mechanism. At bias voltage above 0.5 V, the current transport is due to space charge limited current (SCLC) controlled by an exponential trap distribution in the band gap of CdS. The temperature dependence of the saturation current and ideality factor are well described by tunneling enhanced recombination at junction interface with activation and characteristic tunneling energy values as about 1.79 eV and E₀₀ = 86 meV, respectively. The value of interface state density (N_ss) evaluated from capacitance spectroscopy increases from 2.09x10¹¹ eV^-1cm^-2 (at 300 K) to 2.70x10¹¹ eV^-1cm^-2 (at 363 K). Free carrier concentration of 5.80x10¹³ cm^-3 at room temperature was estimated from capacitance-voltage measurements at 50 kHz.

Abstract: In this paper, semiconductor simulation software ISE TCAD 10.0 was used to simulate W/SiC SBD forward voltage characteristics and reverse voltage characteristics at different temperatures on the basis of theoretical analysis, and the valuable results were achieved. Under the temperature range from 73 K to 773 K, the simulation results of W/SiC Schottky barrier diode forward voltage characteristics showed that forward characteristics were significant influenced by the temperature. At room temperature (303K), if bias voltage was low, the current will be exponential growing with voltage, and the turn-on voltage of W/SiC Schottky barrier diode was about 0.2V. If bias voltage was high, the current increased will be high, and the series resistance effect will become obvious. Under lower bias (2V), a different temperature from 73K to 573K had small impact on reverse current-voltage characteristics. The results showed that the device had the good rectifier characteristics, small reverse current, high breakdown voltage, and the device can steadily and long-term work in high temperature and other complex environment.