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1.
    
The current-voltage (I-V) characteristics of Au/n-GaP Schottky barrier diode was analyzed in wide temperature range of 220–400 K. The conduction mechanism in the low bias region, except for 220 K and 240 K, was identified as tunneling (TN). Nevertheless, thermionic emission (TE) becomes dominant as the voltage increases. The diode parameters were evaluated in this region by TE model incorporating the concept of thin insulating layer. The series resistance (Rs) of the device was found to decrease with increase in temperature. In the 220–320 K temperature range, as reported for most of the Schottky diodes, the zero-bias barrier height (ϕb0) decreases and the ideality factor (η) increases with the decrease of temperature. The value of modified Richardson constant (A**) obtained agrees well with the theoretical value. However, in the 320–400 K range, the variation of η and ϕb0 with temperature shows opposite trend, which is speculated as due to the change in conduction pattern by the temperature induced modifications at the interface.  相似文献   

2.
The electronic properties of metal-organic semiconductor-inorganic semiconductor structure between GaAs and poly(3,4-ethylenedioxithiophene)-block-poly(ethylene glycol) organic film have been investigated via current-voltage and capacitance-voltage methods. The Au/PEDOT/n-GaAs contact exhibits a rectification behavior with the barrier height of 0.69 eV and ideality factor value of 3.94. The barrier height of the studied diode (0.67 eV) is lower than that of Ni/n-GaAs/In (0.85 eV) and Au/n-GaAs/In Schottky diodes. The decrease in barrier height of Au/n-GaAs/In Schottky diode is likely to be due to the variation in the space charge region in the GaAs. The obtained results indicate that control of the interfacial potential barrier for metal/n-GaAs diode was achieved using thin interlayer of the poly(3,4-ethylenedioxithiophene)-block-poly(ethylene glycol).  相似文献   

3.
The electronic parameters and interface state properties of boron dispersed triethanolamine/p-Si structure have been investigated by atomic force microscopy, I-V, C-V-f and G/ω-V-f techniques. The surface topography and phase image of the TEA-B film deposited onto p-Si substrate were analyzed by atomic force microscopy. The atomic force microscopy results show a homogenous distribution of boron particles in triethanolamine film. The electronic parameters (barrier height, ideality factor and average series resistance) obtained from I-V characteristics of the diode are 0.81 eV, 2.07 and 5.04 kΩ, respectively. The interface state density of the diode was found to be 2.54 × 1010 eV cm−2 under Vg = 0. The obtained Dit values obtained from C-V and G/ω measurements are in agreement with each other. The profile of series resistance dependent on voltage and frequency confirms the presence of interface states in boron dispersed triethanolamine/p-Si structure. It is evaluated that the boron dispersed triethanolamine controls the electronic parameters and interface properties of conventional Al/p-Si diode.  相似文献   

4.
    
The Density of States (DOS) is an ingredient of critical importance for the accurate physical understanding of the optoelectronic properties of organic semiconductors. The disordered nature of this class of materials, though, renders the task of determining the DOS far from trivial. Its extraction from experimental measurements is often performed by driving the semiconductor out of thermal equilibrium and therefore requires making assumptions on the charge transport properties of the material under examination. This entanglement of DOS and charge transport models is unfavorable since transport mechanisms in organic semiconductors are themselves still subject of debate. To avoid this, we propose an alternative approach which is based on populating and probing the DOS by means of capacitive coupling in Metal Insulator Semiconductors (MIS) structures while keeping the semiconductor in thermal equilibrium. Assuming a Gaussian shape, we extract the DOS width by numerical fitting of experimental Capacitance–Voltage curves, exploiting the fact that the DOS width affects the spatial distribution of accumulated charge carriers which in turn concurs to define the MIS capacitance. The proposed approach is successfully tested on two benchmark semiconducting polymers, one of n-type and one of p-type and it is validated by verifying the robustness of the extraction procedure with respect to varying the insulator electrical permittivity. Finally, as an example of the usefulness and effectiveness of our approach, we study the static characteristics of thin film transistors based on the aforementioned polymers in the framework of the Extended Gaussian Disorder transport model. Thanks to the extracted DOS widths, the functional dependence of current on the gate voltage is nicely predicted and physical insight on transistor operation is achieved.  相似文献   

5.
6.
High-temperature processing was used to improve the barrier properties of three sets of n-type 4H-SiC Schottky diodes fabricated with Ni Schottky contacts. We obtained an optimum average barrier height of 1.78 eV and an ideality factor of 1.09 using current–voltage measurements on diodes annealed in vacuum at 500°C for 24 h. Nonannealed contacts had an average barrier height of 1.48 eV and an ideality factor of 1.85. The Rutherford backscattering spectra of the Ni/SiC contacts revealed the formation of a nickel silicide at the interface, accompanied by a substantial reduction in oxygen following annealing.  相似文献   

7.
    
Developing Ohmic contact systems or achieving low contact resistance is significant for high-performance semiconductor devices. This work comprehensively investigates the interfacial properties of CrX2N4 (X = C, Si) based field-effect transistors (FETs) with different metal (Ag, Au, Cu, Ni, Pd, Pt, Ti, and graphene) electrodes by using electronic structure calculations and quantum transport simulations. It is highlighted that the stronger interlayer coupling allows CrC2N4 to form an n-type Ohmic contact with Ti electrode in the vertical direction. Furthermore, the absence of tunneling barrier at the CrC2N4–Ti interface greatly improves the electron injection efficiency. On the other hand, the studied metals form Schottky contact with CrC2N4 at the lateral interface due to Fermi level pinning (FLP) effects. Surprisingly, the strong FLP effects restrict the Schottky barrier heights of CrSi2N4-metal contacts to a narrow range. Where Ag, Au, Ni, Pd, Pt, Ti electrodes and Ag, Ti electrodes form ideal ohmic contact with CrSi2N4 in the vertical and lateral directions, respectively, while the other metals form quasi-ohmic contact. Ti exhibits the highest contact performance as the electrode in both CrC2N4 and CrSi2N4 based FETs. The findings may provide fundamental understanding for designing high-performance and energy-efficient FETs based on CrX2N4.  相似文献   

8.
A Richardson constant (RC) of 8.92 Acm?2K?2 from the conventional Richardson plot has been obtained because the current–voltage data of the device quite well obey the thermionic emission (TE) model in 190–320 K range. The experimental nT versus T plot of the device has given a value of T0 = 7.40 K in temperature range of 160–320 K. The deviations from the TE current mechanism at temperatures below 190 K have been ascribed to the patches introduced by lateral inhomogeneity of the barrier heights. Therefore, an experimental RC value of 7.49 A(cmK)?2 has been obtained by considering Tung’s patch model in the temperature range of 80–190 K. This value is in very close agreement with the known value of 8.16 Acm?2K?2 for n-type GaAs.  相似文献   

9.
    
Schottky and Ohmic contacts–based electronics play an important role in highly sensitive detection of biomolecules and neural electric impulses, respectively. The reversible conversion between these two contacts appears especially important for multifunctional sensing by just one biosensor. Here, Schottky barrier height (SBH) is successfully tuned by triboelectric nanogenerator (TENG) and the same device is made to achieve reversible conversion between Schottky contact and Ohmic contact. In the same Schottky to Ohmic reversible (SOR) biosensor, highly sensitive detections of biomolecule (i.e., neurotransmitter) and neural electric signal are achieved at different contact states. The SOR biosensor reveals the feasibility of using one device to realize multifunctional detection. This work proposes a simple and significant method to achieve reversible tuning between the Schottky contact and Ohmic contact on one device by TENG, which exhibits great potential in developing multifunctional and high‐sensitivity biosensors, rectifiers, and other functional electronic devices.  相似文献   

10.
PdAl was selected as a reactive contact to n-(In0.52Al0.48)As with the intention of forming a thin, AlAs-enriched interlayer of graded (In1−xAlx)As semiconductor alloy, following rapid thermal annealing. Selection of PdAl was based on the experimentally established existence of a quasi-reciprocal phase relationship. A Schottky barrier enhancement of 0.07 eV (measured by current-voltage (I-V)) and 0.09 eV (measured by capacitance-voltage (C-V)) was found following a 1-min anneal at 450°C. High-resolution transmission electron microscopy (HRTEM) examination showed the presence of an edge dislocation in the interlayer alloy, suggesting an enrichment of AlAs. Schottky barrier enhancement is in qualitative agreement with the prediction of the combined thermodynamic/kinetic model.  相似文献   

11.
The purpose of this work is to analyze the electrical properties of the metal–semiconductor contact (MSC) in the framework of the theory of complex systems. The effect of inhomogeneity of the different microstructures: polycrystalline, monocrystalline, amorphous metal–semiconductor contact surface is investigated, considering a Schottky diode (SD) as a parallel connection of numerous subdiodes. It has been shown that the polycrystallinity of the metal translates a homogeneous contact into a complex system, which consists of parallel connected numerous elementary contacts having different properties and parameters.  相似文献   

12.
The Poisson's equation and the drift diffusion equations have been used to simulate the current–voltage characteristics of Schottky diode. The potential variation inside the bulk semiconductor near the metal–semiconductor contact was estimated first and then the current as a function of bias through the Schottky diode using silicon parameters were calculated over a wide temperature range. From the simulated current–voltage characteristics the diode parameters were extracted by fitting of current–voltage data into thermionic emission diffusion current equation. The derived barrier parameters are analysed to study the effect of various parameters, e.g. semiconductor thickness, doping concentration, temperature dependence of carrier mobility and energy band gap, on the current–voltage characteristics of Schottky diode in view of the thermionic emission diffusion current equations.  相似文献   

13.
A novel organic crystalline semiconductor, [Cr(DPPP)(DPPM)(Ni-ap)(CO)2] (Cr–Ni OSC) (6a), (DPPP=diphenylphosphino-propanone, DPPM=diphenylphosphino-methane and Ni-ap=nickel apyrazole ring) (6a) was synthesized. Structural characteristics of the Cr–Ni OSC complex have been investigated by IR, 1HNMR, 31P NMR, thermal analysis (TG/DTA), and XRD. Thermal analysis of Cr–Ni OSC implies that, the complex was thermally stable up to 218 °C, and the melting point of it was 193 °C. Two discrete regions of (44.46%, 128–421 °C) and (41.15%, 600–823 °C) by TG analysis of Cr–Ni OSC complex was determined. XRD crystal data of Cr–Ni OSC showed the formation of monoclinic (P21/n). Transmittance and reflectance have been used to determine the optical dispersion and dielectric properties of the Cr–Ni OSC complex in the range of 200–800 nm. The transparency of the complex is 75–80% in the visible range. The optical and transport energy gaps were estimated as 1.87 eV and 2.01 eV respectively. Optical dispersion parameters have been calculated by using single term Sellmeier dispersion relation and Wemple–DiDomenico single oscillator model. Several dispersion parameters were determined by analysis of refractive index dispersion. The optical conductivity, surface and volume energy loss functions, and the electric modulus were also estimated from the optical dielectric constant analysis.  相似文献   

14.
Tungsten, stoichiometric W2N, and nitrogen-rich W2N films were used as Schottky contacts on AlGaN/GaN heterostructures. The nitrogen content in the film was controlled by varying the nitrogen-to-argon gas flow ratio during the reactive sputter deposition. The diode with the nitrogen-rich film exhibited a higher Schottky barrier height and the leakage current was comparable to that of the Ni/Au Schottky contact. Analysis suggested that this was due to the increase of the tungsten nitride work function as the result of higher nitrogen incorporation. Furthermore, after 600°C thermal annealing, the diode was stable and showed no change in the leakage current.  相似文献   

15.
Rhodamine-101 (Rh101) thin films on n-type Si substrates have been formed by means of evaporation, thus Sn/Rh101/n-Si heterojunctions have been fabricated. The Sn/Rh101/n-Si devices are rectifying. The optical energy gaps have been determined from the absorption spectra in the wavelength range of 400 nm to 700 nm. Rh101 has been characterized by direct optical absorption with an optical edge at 2.05 ± 0.05 eV and by indirect optical absorption with␣an optical edge at 1.80 ± 0.05 eV. It was demonstrated that trap-charge-limited current is the dominant transport mechanism at large forward bias. A␣mobility value of μ = 7.31 × 10−6 cm2 V−1 s−1 for Rh101 has been obtained from the forward-bias current–voltage characteristics.  相似文献   

16.
The relationship between the electrical properties and microstructure for annealed Au/Ge/Ni contacts to n-type InP, with an initial doping level of 1017 cm-3, have been studied. Metal layers were deposited by electron beam evaporation in the following sequence: 25 nm Ni, 50 nm Ge, and 40 nm Au. Annealing was done in a nitrogen atmosphere at 250-400‡C. The onset of ohmic behavior at 325‡C corresponded to the decomposition of a ternary Ni-In-P phase at the InP surface and the subsequent formation of Ni2P plus Au10In3, producing a lower barrier height at the InP interface. This reaction was driven by the inward diffusion of Au and outward diffusion of In. Further annealing, up to 400‡C, resulted in a decrease in contact resistance, which corresponded to the formation of NiP and Au9ln4 from Ni2P and Au10In3,respectively, with some Ge doping of InP also likely. A minimum contact resistance of 10-7 Ω-cm2 was achieved with a 10 s anneal at 400‡C.  相似文献   

17.
Two peaks are observed in the capacitance–voltage (C–V) characteristics of electron-transport fullerene (C60 or C70)/Bphen based devices. The experimental results suggest that the mobile carriers generated from unintentional doping and trapped carriers are the origins of these two peaks, just the same as those of hole-transport devices. In addition, the polarity of one C–V peak voltage (the voltage corresponding to the peak capacitance) reverses as the Bphen layer thickness increases. The transient photo-voltage (TPV) signals show a polarity reversal of the internal electric field, confirming the related phenomenon.  相似文献   

18.
The effect of γ-ray exposure on the electrical characteristics of Au/n-GaAs Schottky barrier diodes has been investigated using current–voltage and capacitance–voltage techniques. The results indicate that irradiation with a cumulative dose of 10 Mrad (Si) improves the electrical characteristics of the diode. The parameters like ideality factor, series resistance and reverse leakage current determined from the current–voltage data decreases, whereas the barrier height and rectification ratio increases upon irradiation. The effective barrier height deduced from the capacitance–voltage technique has also increased with irradiation. The irradiated diode shows a higher carrier concentration compared to the virgin diode. The observed overall improvement in the diode quality is attributed to the annealing effect of γ-rays.  相似文献   

19.
    
The Ni/p-InP Schottky diodes(SDs) have been prepared by DC magnetron sputtering deposition. After the diode fabrication, they have been thermally annealed at 700 ℃ for 1 min in N2 atmosphere. Then, the current–voltage characteristics of the annealed and non-annealed(as-deposited) SDs have been measured in the measurement temperature range of 60–400 K with steps of 20 K under dark conditions. After 700 ℃ annealing,an improvement in the ideality factor value has been observed from 60 to 200 K and the barrier height(BH)value approximately has remained unchanged in the measurement temperature range of 200–400 K. The BH of the annealed diode has decreased obeying the double-Gaussian distribution(GD) of the BHs with decreasing measurement temperature from 200 to 60 K. The BH for the as-deposited diode has decreased with decreasing temperature obeying the single-GD over the whole measurement temperature range. An effective Richardson constant value of54:21 A/cm2K2 for the as-deposited SD has been obtained from the modified Richardson plot by the single-GD plot, which is in very close agreement with the value of 60 A/K2cm2 for p-type InP. The series resistance value of the annealed SD is lower than that of the non-annealed SD at each temperature and approximately has remained unchanged from 140 to 240 K. Thus, it can be said that an improvement in the diode parameters has been observed due to the thermal annealing at 700 ℃ for 1 min in N2 atmosphere.  相似文献   

20.
    
The main challenge in developing Schottky-contact OER catalytic devices based on layered double hydroxides (LDHs) is to achieve metal–semiconductor junctions with low contact resistance and high charge transfer capacity. However, due to the presence of high potential barriers and Fermi pinning, conventional Schottky contacts are usually unsatisfactory, resulting in poor-working electrode performance and high energy consumption. In this study, a new concept of “hindrance factor” is introduced to quantify the difficulty of electron transfer, and a low-hindrance factor Schottky contact formed by strong coupling of semiconductor LDH and NiMo alloy clusters is designed. This interface guides charge redistribution, optimizes the bonding and orbital states of adsorption sites, and enhances the targeted adsorption of OH intermediates. The results show that the configured NiMo@NiFeCe-LDH working electrode only needs 1.445 V (vs RHE) to drive the reaction and shows excellent durability in 400 h of testing. At the same time, based on this study, a strategy for screening high-performance Schottky junctions is developed. This strategy provides a bridge for studying interface properties, orbital hybridization, and charge transfer, reveals the potential mechanism for reducing contact resistance, and has important guiding significance for screening high-performance metal–semiconductor electrocatalysts and stability.  相似文献   

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