Electrical Properties Of Diodes Research Articles

Performance Analysis of n-ZnO/p-Si Heterojunction Diode as Function of Zinc Oxide Thin Films Thickness

The n-type Zinc oxide (n-ZnO) nanostructured thin films (TFs) with different thicknesses (211, 325, 433 and 552 nm) were grown onto glass substrates employing the CVD technique at atmospheric pressure. Deposited films were characterized by EDX spectroscopy attached with FE-SEM and XRD techniques to determine the influence of thickness on elemental compositions and crystalline structure of ZnO films, respectively. Also, ZnO TFs were deposited on the p-Si(111) substrates to form different structures of n-ZnO/p-Si heterojunction diodes and then I-V characteristics were studied in the dark. The electrical parameters of the diodes such as rectification ratio (RR), reverse saturation current (Is), ideality factor (), barrier height (b) and series resistance (Rs) were calculated from the I-V measurements. EDX spectra showed that these films were only made from Zn and O elements. XRD patterns presented that the ZnO films possess hexagonal wurtzite structure with preferred orientation along [002] direction. I-V characteristics of the heterojunction diodes revealed rectification behavior and depend on ZnO TFs thickness. Also, electrical parameters of diodes were affected by the prepared film's thickness. It was found that the crystalline structure of the films and electrical properties of diodes were improved with increasing the thickness of ZnO films. It is noted that the best heterojunction diodes were that prepared with thickness (552 nm), where possess lowest value of ideality factor (3.38) and a series resistance (0.84 k) with a highest rectification ratio (1517), compared with other structures. This study offers a simple model for fabricating diodes from semiconductor films.

Optoelectronic investigation of Cu2FeSnS4 quaternary functional photodiodes with IR detection capabilities

Cu2FeSnS4 semiconductor used in the preparation of quaternary photodiodes was synthesized using hydrothermal synthesis. The nanoparticles were then spin coated on a silicon substrate. Nanoparticles were characterized using SEM and EDX where nanoparticles in granular form were seen. Optoelectronic properties were assessed using UV spectra throughout which bandgap energies were calculated. The band gap energy of Cu2FeSnS4 semiconductor was found as 1.22 eV. I – V and I – t characteristics illustrate that Al/p-Si/Cu2FeSnS4/Al heterojunction photodiodes were responsive to daylight and infrared light. Ideality factor, barrier height, saturation current, and photoresponse values were calculated using I - V and I - t data. The ideality factors were calculated as 5.14 and 5.61 for daylight and infrared light (IR) illuminations, respectively. Electrical properties of diodes were checked using C – V and G – V analysis. It was seen that the electrical properties of photodiodes strongly depend on AC signal frequency. Our assessment revealed that frequency related electrical behavior is originated from interface states.

Sr-doped yttrium nickel oxide-based photodetectors

In this research, Sr-doped yttrium nickel oxide-based photodetectors have been fabricated. The electrical properties of diodes have been analyzed by using Cheung and Norde methods. The ideality factors, barrier heights, and series resistances of diodes have been calculated under visible light at different irradiation intensities. In addition, the photoresponse behavior of photodetectors was investigated under visible light at different irradiation intensities. The highest responsivity (R) and detectivity (D*) were calculated as 25.34 mA/W and 7 × 84 1011 Jones, respectively. These results suggest that the photodetectors can be used optoelectronic device applications.

Co-60 gamma irradiation influences on device characteristics of n-SnO2/p-Si heterojunction diodes

Gamma irradiation induced modifications on the structural, morphological, and electrochemical characteristics of the n-SnO2/p-Si heterojunction diodes incorporating their influences on the electrical properties of diode have been systematically studied. The results indicate that irradiation exposure improves the crystallographic structure of the SnO2 layer as expected but, reduce the device capacitance due to changes in the dielectric characteristics of the SnO2. In addition, the surface roughness of the SnO2 thin films become smoother as the irradiation exposures enhanced. On the other hand, low dose irradiation exposure generates the local heating that neutralizes a portion of the dangling bonds which are especially close to the interface between SnO2 and Si. Hence, interface state density decreases after low dose irradiation exposure. However, high irradiation doses create a large number of oxygen vacancies and interstitial defect. These generated defect sites lead to changes on the barrier potential and conduction mechanism of the diode. It can be concluded that complex irradiation induced mechanism has been observed for SnO2/Si heterojunction diodes. Any irradiation-induced changes on the film structures and electrochemical parameters directly affect the electrical responses of the diodes.

Characterization of thin irradiated epitaxial silicon sensors for the CMS phase II pixel upgrade

The high-luminosity upgrade of the Large Hadron Collider foreseen for 2023 resulted on the decision to replace the tracker system of the CMS experiment. The innermost layer of the new pixel detector will experience fluences in the order of ϕeq ≈ 1016 cm−2 and a dose of ≈ 5 MGy after an integrated luminosity of 3000 fb−1. Several materials and designs are under investigation in order to build a detector that can withstand such high fluences. Thin planar silicon sensors are good candidates to achieve this goal since the degradation of the signal produced by traversing particles is less severe than for thicker devices. A study has been carried out in order to characterize highly irradiated planar epitaxial silicon sensors with an active thickness of 100 μm. The investigation includes pad diodes and strip detectors irradiated up to a fluence of ϕeq = 1.3 × 1016 cm−2, and 3 × 1015 cm−2, respectively. The electrical properties of diodes have been characterized using laboratory measurements, while measurements have been carried out at the DESY II test beam facility to characterize the charge collection of the strip detectors. A beam telescope has been used to determine precisely the impact position of beam particles on the sensor. This allows the unbiased extraction of the charge deposited in the strip sensor and good identification of the noise. In this paper, the results obtained for p-bulk sensors are shown. The charge collection efficiency of the strip sensors is 90% at 1000 V after a fluence of ϕeq = 3 × 1015 cm−2. The irradiated diodes show charge multiplication effects. The impact of the threshold applied to a detector on its efficiency is also discussed.

Electrical properties of silicon schottky diodes containing metal films of various compositions

Au x Ti100 − x /n-Si Schottky diodes are fabricated and studied; in addition, the electrical properties of diodes containing metal films with varying composition (x = 0, 14, 30, 38, 60, 80, and 100) are also studied. Using X-ray phase analysis, it is established that the film of Au38Ti62 composition has the amorphous structure, while the remaining films Au x Ti100 − x possess the polycrystalline structure. The main parameters of the Schottky diodes are determined in relation to the composition and structure of the metal films. As a result, it is shown that the electrical properties of Au x Ti100 − x /n-Si Schottky diodes are related to variations in the composition and structure of metal films.

Electrical and photovoltaic properties of heterojunction diode based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)

n-Si/p-PEDOT-PSS heterojunction diode was fabricated by deposition of poly(3,4- ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) onto n-type Si wafer using spin coating. Its electrical properties of the diode were investigated by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The field emission scanning electron microscopy (FE-SEM) was used to determine the surface quality. SEM result indicates that the surface morphology of the PEDOT-PSS film spin coated on n-Si substrate is almost homogeneous. Diode parameters such as the ideality factor, barrier height and series resistance were calculated using Cheung’s method and C-V measurements. I-V characteristics under dark and illumination conditions were performed to characterize the photovoltaic behavior of the diode.

High effective Schottky barriers on n-type InP using Zn-based metallizations and rapid thermal annealing

Surface barrier diodes using different Zn-based metallizations, which were alloyed using rapid thermal annealing in order to make low-leakage, high barrier metal-semiconductor diodes on n-type InP, have been studied. The electrical properties of diodes using Cr in between the Zn layer and the InP are poor, because Cr and P forms a diffusion barrier-like layer adjacent to the semiconductor surface, which is hard to overcome and, more important, shunts the diode because it forms low effective barriers to n-type InP. For Au/Cr/Zn/Au/lnP diodes, high effective Schottky barriers of 0.76 eV from J-V characteristics and 1.23 eV from C-V characteristics have been measured for the same barrier diodes, indicating that the surface is not fully covered with the high effective barrier height interfacial phase, but that lower effective barrier height interfacial phases are also present. The dominant transport mechanism of carriers across these metal-semiconductor diodes is found to be thermionic emission from J-V-T measurements. and the leakage current density measured at -1 V is 8*10-6-10-5 A cm-2. From depth profiling using Rutherford backscattering spectrometry and near-surface imaging using scanning electron microscopy it is seen that In is depleted from the InP surface due to Zn-P/Cr-P stable phase formation and that it either agglomerates at the surface of the metallization or is incorporated into the Au layer forming stable Au-In and In-O compounds.

Interfacial oxide growth and filling-up behaviour of the micro-gap in silicon fusion bonding processes

In the silicon fusion bonding (SFB) process, the influence of post-annealing atmospheres on the micro-gap existing at the Si-Si bonding interface was investigated with the observation of ultrasonic images, angle lap-stained junctions and cross section SEM morphologies. Additionally, the bonding strength and the electrical properties of diodes were compared after annealing processes at 100/dg fo 10 s to 10 h in wet O2, dry O2 and N2 atmospheres. Our results show that a significant saving of annealing time necessary to eliminate the non-contact micro-gap region having a width of ≤ 0.1 μm can be obtained if the hydrogenbonded wafer pair is pre-stabilized and post-annealed in wet O2 (95°C water bubbling) rather than in a dry O2 or N2 atmosphere. Based on the above result, we propose that the stabilizing and annealing step in highlt oxidizing atmosphere has an important role in the oxide filling-up phenomenon between wafer and wafer gap, in addition to the well-known mechanism of wafer plastic deformation at high temperature followed by solid-state diffusion of Si and O atoms.

Theoretical Analysis of Radiation Effects on Silicon Power Diode Characteristics

A theoretical study has been carried out on the effect of Radiation upon the electrical properties of silicon power diodes. Computer program “PDIORAD” is developed to solve the diode equations and to introduce the operating conditions and radiation effects upon its parameters. Temperature increase interrupts the electrical properties of the diode in the direction of drop voltage decrease across the p-n junction. The model is analyzed under the influence of different radiation type (gamma-rays, neutrons, protons and electrons) with various dose levels and energies. The carriers diffusion length are seriously affected leading to a large increase in the forward voltage. These effects are found to be function of radiation type, fluence and energy.

The rectifying contact of gold on etched CdTe single crystals

An investigation was made of the fundamental electrical properties of diodes prepared by the precipitation of gold on mechanically polished and chemically etched surfaces of n-type CdTe monocrystals. The forward I–U characteristics measured in the temperature range from 210 to 300 K can be explained by Schottky's theory of metal–semiconductor junction with recombination in the space charge region. The reverse I–U characteristics are in good agreement with Schottky's theory at room temperature only. At lower temperatures a strong increase of the current with increasing voltage was observed. This effect may be explained by the current tunnelling through the high resistivity layer formed between the metal and the semiconductor. [Russian Text Ignored].

Radiation damage and substitutional chemical impurity effects in single-crystal germanium bombarded with 40-keV B+, Al+, Ga+, Ge+, P+, As+, and Sb+ ions

Isochronal anneal studies have been made on n- and p-type germanium bombarded with germanium and several substitutional impurities, using the four-point and thermoelectric probes as means of indicating changes in sheet resistivity and majority carrier type. Electrical properties of diodes made from type converted samples were also determined. All bombardments were performed at 40 keV in a 24-in.-radius electromagnetic isotope separator at room temperature. These studies revealed the following. (1) Heavy-particle bombardment of germanium introduces acceptor states regardless of the identity of the bombarding species. (2) Annealing curves for n-type germanium indicate a two-stage process; details of the annealing process are dependent on the ion species used and the crystal orientation bombarded. (3) There is a crystallographic and mass dependence on the amount of change in sheet resistivity produced in n-type germanium. (4) Type conversion temperatures in p-type germanium were observed to occur at 450–475 °C for phosphorus, ~500 °C for arsenic, and slightly greater than 500 °C for antimony, suggesting that the ease of moving a particular species into an active lattice position is related to its atomic size. (5) Voltage–current and capacitance measurements indicate that large-area diodes of relatively good properties and reproducibility can be made by ion implantation in germanium.

Gunn oscillations in indium arsenide

Gunn oscillations in indium arsenide, measuring electrical properties of diodes, noting current voltage characteristics as function of applied stress