Investigation of current-voltage characteristics of Ni/GaN Schottky barrier diodes for potential hemt applications

In the present work, the I-V characteristics of Ni/GaN Schottky diodes have been studied. The Schottky diodes, having different sizes using Ni/Au and ohmic contacts using Ti/Al/Ni/Au were made on n-GaN. The GaN was epitaxially grown on c-plane sapphire by metal organic chemical vapor deposition (MOCVD) technique and had a thickness of about 3.7 μm. The calculated ideality factor and barrier height from current-voltage (I-V) characteristics (at 300 K) for two GaN Schottky diodes were close to ~1.3 and ~ 0.8 eV respectively. A high reverse leakage current in the order of 10 – 4A/cm2 (at – 1 V) was observed in both diodes. A careful analysis of forward bias I-V characteristics showed very high series resistance and calculation for ideality factor indicated presence of other current transport mechanism apart from thermionic model at room temperature. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2202

Performance Analysis of GaN/AlGaN HEMTs Passivation using Inductively Coupled Plasma Chemical Vapour Deposition and Plasma Enhanced Chemical Vapour Deposition Techniques

In the present paper SiN thin film has been studied as a passivation layer and its effect on AlGaN/GaN HEMTs is investigated using two different deposition techniques i.e PECVD and ICPCVD. AlGaN/GaN HEMTs devices passivated with optimised SiN film have delivered lower gate leakage current (from μA to nA). Device source drain saturation current (Ids) increased from 400mA/mm to ~550 A/mm and the peak extrinsic trans-conductance increased from 100 mS/mm to 170 mS/mm for a 0.8 μm HEMT device. The optimised SiN passivation process has resulted in reduced current collapse and increased breakdown voltage for HEMT devices.

Studying the Methods to Determine the Age of Ink: A Critical Review of Ink Dating Methods

On the basis of the type of ink, pen inks are classified as ballpoint pens or non-ballpoint pens. Ballpoint pen inks are oil-based inks (ballpoint pens). While non-ballpoint pen inks are water-based inks (gel pens, fountain pens, pilot pens, fiber tip pens, etc.). Different approaches related to the determination of the age of ink were proposed in the literature, including ballpoint pen inks, non-ballpoint pen inks and stamp pad inks. This study provides a comprehensive appreciation of analytical research studies that were published from the year 2000 to year 2020 on the determination of the age of inks. Owing To contemporary technological advancements, the process has been developed in many folds. However, its reliability is questioned due to the variability in methods and results. Research works related to the aging of ink have been compiled to assist the researchers and the forensic document examiners and to provide an overall insight regarding the works done so far. In an attempt to unravel this issue of questioned document examination, a critical and systematic review of the literature is proposed to encourage the usage of various tools and techniques necessary to establish the age of ink in different case works

Design and Fabrication of Multi-finger Field Plate for Enhancement of AlGaN/GaN HEMT Breakdown Voltage

The design and fabrication of gate/source connected multi-finger field plate structures using TCAD ATLAS simulation software is presented. The designed field plate structures are fabricated on indigenous AlGaN/GaN HEMT devices. AlGaN/GaN HEMT devices with field plate structures exhibit about three times improvement in breakdown voltage of device and are in close agreement with the simulation results. Integration of field plates in device have resulted in higher VDS (drain to source voltage) operation and improvement in output power of AlGaN/GaN HEMT devices. Incorporation of field plates also decrease the reverse leakage current of HEMT devices

A Comparative Study on Class Characteristics of Devanãgri Script Writers from Three Different States of India

India is a multilingual country. Hindi is the national language of India and Devanãgri script is used to write Hindi language. Various documents with legal value are made in Devanãgri script, which may be questioned for their authenticity and authorship. Sufficient research has been done and reported about different scripts. However, researches based on Devanãgri script are limited. This study focuses on finding the significant class characteristics of writers from three different states of India, namely, Bihar, Madhya Pradesh and Punjab. The data was also statistically analysed using Pearson’s Chi-Square test for its significance. Handwriting samples from 300 subjects were collected from three different states of India to analyze various class characteristics in Devanãgri script. The samples were examined qualitatively and statistically. Various general characteristics were selected for the analysis and characteristic features were tabulated after qualitative examination. Statistical analysis showed that the data was statistically significant. The general characteristics selected for the analysis and comparison of the handwriting samples in Devanãgri script were found to be significant. The impact of regional scripts on the Devanãgri script should be performed, as the influence of regional language could be seen in the samples collected from Punjab

Evaluation of laryngoscopic view, intubation difficulty and sympathetic response during direct laryngoscopy in sniffing position versus simple head extension: a clinical comparative study

Background: Proper position of the head and the neck is important for optimizing laryngoscopic view and for ease of endotracheal intubation.We compared two different positions, sniffing position and simple head extension during direct laryngoscopy on the basis of laryngoscopic view, intubation difficulty and sympathetic response. Methodology: One hundred twenty patients of age group 20-50 years, scheduled for elective surgeries under general anaesthesia were divided into two equal groups in a randomized fashion. In group A (n = 60), sniffing position during laryngoscopy and intubation; and in group B(n =60),simple head extension position during laryngoscopy and intubation. Laryngoscopy view, ease of intubation and hemodynamic parameters were recorded. Results: Demographic data and the different parameters for assessment of difficult airway were similar in both groups. Glottic visualization grade was superior in group A and intubation difficulty score were higher in Group B (P < 0.05), Hemodynamic parameters at different time intervals were comparable. Conclusion: Sniffing position during laryngoscopy was found to be superior to simple head extention position in respect of better glottis visualization and ease of intubation though no difference in sympathetic response to intubation was found

Investigation on de-trapping mechanisms related to non-monotonic kink pattern in GaN HEMT devices

This article reports an experimental approach to analyze the kink effect phenomenon which is usually observed during the GaN high electron mobility transistor (HEMT) operation. De-trapping of charge carriers is one of the prominent reasons behind the kink effect. The commonly observed non-monotonic behavior of kink pattern is analyzed under two different device operating conditions and it is found that two different de-trapping mechanisms are responsible for a particular kink behavior. These different de-trapping mechanisms are investigated through a time delay analysis which shows the presence of traps with different time constants. Further voltage sweep and temperature analysis corroborates the finding that different de-trapping mechanisms play a role in kink behavior under different device operating conditions

Barrier height enhancement of Ni/GaN Schottky diode using Ru based passivation scheme

Wet chemical passivation of n-GaN surface using Ru based solution has been reported. X-ray photoelectron spectroscopy characterization of the GaN surface revealed removal of surface oxides by the introduction of Ru complex species. Ni/n-GaN Schottky barrier diodes were fabricated on passivated GaN and a remarkable improvement in Schottky barrier height from 0.76eV to 0.92eV was observed

Nickel substitution induced effects on gas sensing properties of cobalt ferrite nanoparticles

Ni2+ ion induced unusual conductivity reversal and an enhancement in the gas sensing properties of ferrites based gas sensors, is reported. The Co1-xNixFe2O4 (for x = 0, 0.5 and 1) nanoparticles were synthesized by wet chemical co-precipitation method and gas sensing properties were studied as a function of composition and temperature. The structural, morphological and microstructural characterization revealed crystallite size of in the range 10-20 nm with porous morphology consisting of nano-sized grains. The Energy Dispersive X-ray (EDX) mapping confirms homogeneous distribution of Co, Ni, Fe and O elements in the ferrites. The non-stoichiometry of the inverse spinel type ferrites and the relative concentration of Ni3+/Co3+ defects were studied using X-ray photoelectron spectroscopy. It is found that the addition of Ni2+ ions into cobalt ferrite shows preferred selectivity towards CO gas at high temperature (325 degrees C) and ethanol gas at low temperature (250 degrees C), unlike undoped cobalt ferrite or undoped nickel ferrite, which show similar response for both these gases. Moreover, an unusual conductivity reversal is observed, except cobalt ferrite due to the difference in reactivity of the gases as well as characteristic non-stoichiometry of ferrites. This behavior is highly gas ambient dependent and hence can be well-exploited for selective detection of gases. (C) 2015 Elsevier B.V. All rights reserved