Electrical Properties of Al/p-Si Structures with Colchicine Organic Thin Film

In this study, we have fabricated an Al/Colchicine/p-Si structure and have investigated its current– voltage (I–V) and capacitance–voltage (C–V) characteristics at room temperature. The barrier height and ideality factor values of 0.68 eV and 3.22, respectively, have been obtained from the I-V plot. The value of the barrier height was compared with the barrier height value of 0.50 eV of a conventional Al/p-Si diode. This was attributed to the Colchicine organic film modifying the effective barrier height by affecting the space charge region of the inorganic Si semiconductor substrate. By using C – 2-V characteristics the diffusion potential value has been extracted as 1.32 V. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3514

Properties of Pt Schottky Type Contacts On High-Resistivity CdZnTe Detectors

In this paper we present studies of the I-V characteristics of CdZnTe detectors with Pt contacts fabricated from high-resistivity single crystals grown by the high-pressure Brigman process. We have analyzed the experimental I-V curves using a model that approximates the CZT detector as a system consisting of a reversed Schottky contact in series with the bulk resistance. Least square fits to the experimental data yield 0.78-0.79 eV for the Pt-CZT Schottky barrier height, and <20 V for the voltage required to deplete a 2 mm thick CZT detector. We demonstrate that at high bias the thermionic current over the Schottky barrier, the height of which is reduced due to an interfacial layer between the contact and CZT material, controls the leakage current of the detectors. In many cases the dark current is not determined by the resistivity of the bulk material, but rather the properties of the contacts; namely by the interfacial layer between the contact and CZT material.Comment: 12 pages, 11 figure

Capacitance-conductance characteristics of Au/Ti/Al2O3/n-GaAs structures with very thin Al2O3 interfacial layer

High-k Al2O3 with metallic oxide thickness of about 3 nmon n-type GaAs substrate has been deposited by the atomic layer deposition (ALD) technique. Thus, it has been formed the Au-Ti/Al2O3/n-GaAs MIS structures. It has been seen that the MIS structure exhibits excellent capacitance-voltage (C-V) and current-voltage (I-V) properties at 300 K. The saturation current of the forward bias and reverse bias I-V characteristics was the same value. An ideality factor value of 1.10 has been obtained from the forward bias I-V characteristics. The C-Vcharacteristics of the structure have shown almost no hysteresis from +3 Vto -10 Vwith frequency as a parameter. The reverse biasC-V curves have exhibited a behavior without frequency dispersion and almost hysteresis at each frequency from 10 kHz to 1000 kHz. © 2015 IOP Publishing Ltd

Broadband terahertz heterodyne spectrometer exploiting synchrotron radiation at megahertz resolution

International audienceA new spectrometer allowing both high resolution and broadband coverage in the terahertz (THz) domain is proposed. This instrument exploits the heterodyne technique between broadband synchrotron radiation and a quantum cascade laser (QCL) based molecular THz laser that acts as the local oscillator (LO). Proof of principle for exploitation for spectroscopy is provided by the recording of molecular absorptions of hydrogen sulfide (H 2 S) and methanol (CH 3 OH) around 1.073 THz. Ultimately, the spectrometer will enable to cover the 1-4 THz region in 5 GHz windows at Doppler resolution

Oral treatment with a zinc complex of acetylsalicylic acid prevents diabetic cardiomyopathy in a rat model of type-2 diabetes: activation of the Akt pathway.

BACKGROUND: Type-2 diabetics have an increased risk of cardiomyopathy, and heart failure is a major cause of death among these patients. Growing evidence indicates that proinflammatory cytokines may induce the development of insulin resistance, and that anti-inflammatory medications may reverse this process. We investigated the effects of the oral administration of zinc and acetylsalicylic acid, in the form of bis(aspirinato)zinc(II)-complex Zn(ASA)2, on different aspects of cardiac damage in Zucker diabetic fatty (ZDF) rats, an experimental model of type-2 diabetic cardiomyopathy. METHODS: Nondiabetic control (ZL) and ZDF rats were treated orally with vehicle or Zn(ASA)2 for 24 days. At the age of 29-30 weeks, the electrical activities, left-ventricular functional parameters and left-ventricular wall thicknesses were assessed. Nitrotyrosine immunohistochemistry, TUNEL-assay, and hematoxylin-eosin staining were performed. The protein expression of the insulin-receptor and PI3K/AKT pathway were quantified by Western blot. RESULTS: Zn(ASA)2-treatment significantly decreased plasma glucose concentration in ZDF rats (39.0 +/- 3.6 vs 49.4 +/- 2.8 mM, P < 0.05) while serum insulin-levels were similar among the groups. Data from cardiac catheterization showed that Zn(ASA)2 normalized the increased left-ventricular diastolic stiffness (end-diastolic pressure-volume relationship: 0.064 +/- 0.008 vs 0.084 +/- 0.014 mmHg/microl; end-diastolic pressure: 6.5 +/- 0.6 vs 7.9 +/- 0.7 mmHg, P < 0.05). Furthermore, ECG-recordings revealed a restoration of prolonged QT-intervals (63 +/- 3 vs 83 +/- 4 ms, P < 0.05) with Zn(ASA)2. Left-ventricular wall thickness, assessed by echocardiography, did not differ among the groups. However histological examination revealed an increase in the cardiomyocytes' transverse cross-section area in ZDF compared to the ZL rats, which was significantly decreased after Zn(ASA)2-treatment. Additionally, a significant fibrotic remodeling was observed in the diabetic rats compared to ZL rats, and Zn(ASA)2-administered ZDF rats showed a similar collagen content as ZL animals. In diabetic hearts Zn(ASA)2 significantly decreased DNA-fragmentation, and nitro-oxidative stress, and up-regulated myocardial phosphorylated-AKT/AKT protein expression. Zn(ASA)2 reduced cardiomyocyte death in a cellular model of oxidative stress. Zn(ASA)2 had no effects on altered myocardial CD36, GLUT-4, and PI3K protein expression. CONCLUSIONS: We demonstrated that treatment of type-2 diabetic rats with Zn(ASA)2 reduced plasma glucose-levels and prevented diabetic cardiomyopathy. The increased myocardial AKT activation could, in part, help to explain the cardioprotective effects of Zn(ASA)2. The oral administration of Zn(ASA)2 may have therapeutic potential, aiming to prevent/treat cardiac complications in type-2 diabetic patients

METALLIC POLYTHIOPHENE INORGANIC SEMICONDUCTOR SCHOTTKY DIODES

An examination of the rectification properties of organic conductor/inorganic semiconductor/metal Schottky diodes has been made, in which freshly prepared polythiophene has been used as metal, and n-Si and n-GaAs as semiconductors. Polythiophene films were electrochemically obtained on glass substrates covered with Au in acetonitrile/0.25 M LiClO4 solution. The metallic polythiophene polymer has provided a good rectifying contact to the n-Si and n-GaAs semiconductors. The processing and I-V and C-V measurements of the devices were done at room temperature in laboratory atmosphere. The forward I-V characteristics of the metallic polythiophene/n-Si and the metallic polythiophene/n-GaAs Schottky diodes have exhibited ideality factors of 2.40 and 2.69, respectively. However, values obtained for the barrier height of these Schottky diodes could be sufficient for many device applications. In addition, the work function of the polythiophene was determined as 4.81 eV

The determination of interface state energy distribution of the H-terminated Zn/p-type Si Schottky diodes with high series resistance by the admittance spectroscopy

Analysis of Zn/p-Si Schottky diodes (SDs) with high resistivity has been given by admittance spectroscopy. The importance of the series resistance in the determination of energy distribution of interface states and especially their relaxation time in the SDs with high resistivity has been considered. The effect of the series resistance on capacitance-conductance/frequency characteristics has been given by comparing experimental data with theoretical data. The interface state density A,, from the admittance spectroscopy ranges from 1.0 X 10(12) cm(-2) eV(-1) in 0.720-E-v eV to 2.03 x 10(12) cm(-2) eV(-1) in 0.420-E-v eV. Furthermore, the relaxation time ranges from 4.20 x 10(-5) s in (0.420-E-v) eV to 3.20 x 10(-4) s in (0.720-E-v)eV. It has been seen that the interface state density has a very small distribution range (1.0-2.03 x 10(12) cm(-2) eV(-1)) that is ascribed to the predominant termination with hydrogen of the silicon surface after HF treatment. (C) 2003 Elsevier Ltd. All rights reserved

Effect of thermal annealing in nitrogen on the I-V and C-V characteristics of Cr-Ni-Co alloy/LEC n-GaAs Schottky diodes

The Schottky barrier height Phi(b) and ideality factor n of Cr-Ni-Co alloy Schottky contacts on an n-LEC GaAs substrate have been measured using current-voltage (I-V) and capacitance-voltage (C-V) techniques after different thermal annealings for 5 min in N-2 (temperature range from 300 to 600 degrees C), The values of Phi(b) and n for the forward I-V characteristics range from 0.65 and 1.001 eV at room temperature (RT) to 0.86 and 1.095 eV at 400 degrees C. Thereby, the barrier height enhancement has been explained in terms of the presence of microclusters of one or more interface phases produced by reactions between the alloy and GaAs or the native oxide layer. The stability value of 1.010 for n from the RT to 300 degrees C annealing has been ascribed to reduction of the native oxide layer on the GaAs surface by Cr in the alloy. The C-V relationship of the Cr-Ni-Co/n-GaAs Schottky diode at 1 MHz gives values of 0.68, 0.74 and 0.85 eV for Phi(b) at RT, 100 degrees C and 200 degrees C annealing temperatures respectively The fact that the C-2-V curves after annealing above 200 degrees C show two linear regions separated by a transition segment has been attributed to the diffusion of Cr into GaAs during the thermal annealing process

The Cu/n-GaAs Schottky barrier diodes prepared by anodization process

The metal-insulating semiconductor (MIS) Cu/n-GaAs diodes with thin anodic-insulating layer, which is formed by anodic oxidization on the n-GaAs substrate in aqueous 4C(2)H(6)O(2) + 2H(2)O + 0.1H(3)PO(4) electrolyte with pH = 2.02; anodically untreated control Cu/n-GaAs diodes; and anodically treated Cu/nGaAs diodes (several steps of anodization in the same electrolyte followed by a dip in diluted aqueous HCl solution and a subsequent rinse in deionized water) have been prepared. The anodization has increased the barrier heights as well as the ideality factors. We have obtained barrier heights of approximately 0.68 eV, 0.90 eV, and 0.92 eV for the control sample, anodically treated sample, and MIS sample, respectively, adding the contribution caused by image-force effect only. Thus, the barrier height has been increased by at least 140 meV. Furthermore, we have calculated a mean tunneling-barrier height of X = 0.025 eV for the MIS Cu/n-GaAs Schottky barrier diode (SBD)