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The purpose of this paper is to consider the changing of profile of heterostructure during growth with changing of temperature of substrate.

The authors introduced an analytical approach for the analysis of technological process.

The authors formulate the condition for minimization of changing of the profile.

The approach gives a possibility to analyze mass and heat transports in a heterostructure without cross-linking of solutions on interfaces between layers of the heterostructure with account nonlinearity of these transports and variation in time of their parameters.

The purpose of this paper is to develop an efficient numerical algorithm for the self‐consistent solution of Schrodinger and Poisson equations in one‐dimensional systems. The goal is to compute the charge‐control and capacitance‐voltage characteristics of quantum wire transistors.

The paper presents a numerical formulation employing a non‐uniform finite difference discretization scheme, in which the wavefunctions and electronic energy levels are obtained by solving the Schrödinger equation through the split‐operator method while a relaxation method in the FTCS scheme (“Forward Time Centered Space”) is used to solve the two‐dimensional Poisson equation.

The numerical model is validated by taking previously published results as a benchmark and then applying them to yield the charge‐control characteristics and the capacitance‐voltage relationship for a split‐gate quantum wire device.

The paper helps to fulfill the need for C‐V models of quantum wire device. To do so, the authors implemented a straightforward calculation method for the two‐dimensional electronic carrier density n(x,y). The formulation reduces the computational procedure to a much simpler problem, similar to the one‐dimensional quantization case, significantly diminishing running time.

This study aims to investigate the effects of indium composition on surface morphology and optical properties of indium gallium nitride on gallium nitride (InGaN/GaN) heterostructures.

The InGaN/GaN heterostructures were grown on flat sapphire substrates using a metal-organic chemical vapour deposition reactor with a trimethylindium flow rate of 368  sccm. The indium composition of the InGaN epilayers was controlled by applying different substrate temperatures. The surface morphology and topography were observed using field emission scanning electron microscope (F.E.I. Nova NanoSEM 450) and atomic force microscopy (Bruker Dimension Edge) with a scanning area of 10 µm × 10 µm, respectively. The compositional analysis was done by Energy Dispersive X-Ray Analysis. Finally, the ultraviolet-visible (UV-Vis) spectrophotometer (Agilent Technology Cary Series UV-Vis-near-infrared spectrometer) was measured from 200 nm to 1500 nm to investigate the optical properties of the samples.

The InGaN/GaN thin films have been successfully grown at three different substrate temperatures. The indium composition reduced as the temperature increased. At 760 C, the highest indium composition was obtained, 21.17%. This result was acquired from the simulation fitting of ω−2θ scan on (0002) plane using LEPTOS software by Bruker D8 Discover. The InGaN/GaN shows significantly different surface morphologies and topographies as the indium composition increases. The thickness of InGaN epilayers of the structure was ∼300 nm estimated from the field emission scanning electron microscopy. The energy bandgap of the InGaN was 2.54 eV – 2.79 eV measured by UV-Vis measurements.

It can be seen from this work that changes in substrate temperature can affect the indium composition. From all the results obtained, this work can be helpful towards efficiency improvement in solar cell applications.

High packaging density in the present VLSI era builds an acute power crisis, which limits the use of MOSFET device as a constituent block in CMOS technology. This leads researchers in looking for alternative devices, which can replace the MOSFET in CMOS VLSI logic design. In a quest for alternative devices, tunnel field effect transistor emerged as a potential alternative in recent times. The purpose of this study is to enhance the performances of the proposed device structure and make it compatible with circuit implementation. Finally, the performances of that circuit are compared with CMOS circuit and a comparative study is made to find the superiority of the proposed circuit with respect to conventional CMOS circuit.

Silicon–germanium heterostructure is currently one of the most promising architectures for semiconductor devices such as tunnel field effect transistor. Analytical modeling is computed and programmed with MATLAB software. Two-dimensional device simulation is performed by using Silvaco TCAD (ATLAS). The modeled results are validated through the ATLAS simulation data. Therefore, an inverter circuit is implemented with the proposed device. The circuit is simulated with the Tanner EDA tool to evaluate its performances.

The proposed optimized device geometry delivers exceptionally low OFF current (order of 10^−18 A/um), fairly high ON current (5x10^−5 A/um) and a steep subthreshold slope (20 mV/decade) followed by excellent ON–OFF current ratio (order of 10^13) compared to the similar kind of heterostructures. With a very low threshold voltage, even lesser than 0.1 V, the proposed device emerged as a good replacement of MOSFET in CMOS-like digital circuits. Hence, the device is implemented to construct a resistive inverter to study the circuit performances. The resistive inverter circuit is compared with a resistive CMOS inverter circuit. Both the circuit performances are analyzed and compared in terms of power dissipation, propagation delay and power-delay product. The outcomes of the experiments prove that the performance matrices of heterojunction Tunnel FET (HTFET)-based inverter are way ahead of that of CMOS-based inverter.

Germanium–silicon HTFET with stack gate oxide is analytically modeled and optimized in terms of performance matrices. The device performances are appreciable in comparison with the device structures published in contemporary literature. CMOS-like resistive inverter circuit, implemented with this proposed device, performs well and outruns the circuit performances of the conventional CMOS circuit at 45-nm technological node.

An simple model for the simulation of the electrical behaviour of several types of junction controlled field‐effect transistors is proposed. It is based on the calculation of the carrier concentration in the channel by means of a self‐consistent solution of Schrödinger and Poisson's equation in the direction perpendicular to the current flow. Based on the carrier concentration the dc, the small‐signal, and also the noise properties of the devices may be simulated. The calculated characteristics of a sub‐quarter micron gate GaAs MESFET, a δ‐doped GaAs FET and a Velocity Modulation Transistor will be presented and discussed.

This paper aims to report on the use of radio frequency nitrogen plasma‐assisted molecular beam epitaxy (RF‐MBE) to grow high‐quality n‐type In_0.47Ga0.53N/GaN on Si(111) substrate using AlN as a buffer layer.

Structural analyses of the InGaN films were performed by using X‐ray diffraction, atomic force microscopy, and Hall measurement. Metal‐semiconductor‐metal (MSM) photodiode was fabricated on the In_0.47Ga0.53N/Si(111) films. Electrical analysis of the MSM photodiodes was carried out by using current‐voltage (I‐V) measurements. Ideality factors and Schottky barrier heights for Ni/In_0.47Ga0.53N, was deduced to be 1.01 and 0.60 eV, respectively.

The In_0.47Ga0.53N MSM photodiode shows a sharp cut‐off wavelength at 840 nm. A maximum responsivity of 0.28 A/W was achieved at 839 nm. The detector shows a little decrease in responsivity from 840 to 200 nm. The responsivity of the MSM drops by nearly two orders of magnitude across the cut‐off wavelength.

Focuses on III‐nitride semiconductors, which are of interest for applications in high temperature/power electronic devices.

We have developed a two‐dimensional model for quantum‐well lasers which solves, self‐consistently, the semiconductor equations together with the complex scalar wave equation and the photon rate equation. To predict the threshold current accurately we have included the wavelength‐ and position‐dependence of the gain and the spontaneous emission. For the complex wave equation successive over relaxation (SOR) is used with two adaptive acceleration parameters for the complex wave amplitude and for the eigenvalue. Since the rate equation near threshold can be driven into divergence during iteration for a steady state solution, we have introduced a special damping technique to overcome this problem. Our model enables us to predict the characteristics of a quantum‐well laser with a minimal number of empirical constants. The output of the model includes light‐current characteristics, and the current and optical field intensity distributions. We show the results of a calculation for a graded‐index separate‐confinement heterostructure single quantum‐well (GRIN‐SCH SQW) laser.

The purpose of this paper is to: analyze the changing properties of epitaxial layers, manufactured in the considered reactor, with the changing parameters of the growth taking into account native convection; and development of the most common analytical approach to describe the technological process.

In this paper a vertical reactor for gas phase epitaxy is considered that consists of an external casing, a keeper of substrate with a substrate and a spiral around the casing in area of the growth zone to generate induction heating in order to activate the chemical reactions in the decay of reagents and the growth of the epitaxial layer by using the reagents. The authors introduce an analytical approach to analyze nonlinear mass and heat transport with account variation in space and time parameters.

The authors find conditions to improve properties of epitaxial layers.

Growth regimes at atmospheric and low pressure have been compared and analyzed for their influence of the native convection on the growth of the epitaxial layers. Accounting for the calculated results, recommendations have been formulated to improve the properties of the epitaxial layers.

It has been recently shown that diffusion of dopant during doping of inhomogeneous structure could be accelerated or decelerated in comparison with diffusion of dopant in structure with averaged diffusion coefficient. As a continuation of previous work, the purpose of this paper is to introduce an approach of estimating the limited value of acceleration of the dopant diffusion by choosing the dependence of the dopant diffusion coefficient on the coordinates.

The authors analyzed relaxation of concentration of dopant during diffusion in inhomogeneous material. The authors determine conditions for maximal acceleration and deceleration of diffusion of dopant. The authors introduced analytical approach for analysis of dopant diffusion in inhomogeneous material.

The authors determine conditions for maximal acceleration and deceleration of diffusion of dopant.

It has been shown that dopant diffusion could be decelerated essentially to a greater extent, rather than accelerated.

Sensing technology has been extensively researched and used due to its applications in industrial production and daily life. Due to inherent limitations of conventional silicon-based technology, researchers are now-a-days paying more attention to flexible electronics to design low-cost, high-sensitivity devices. This observational and analytical study aims to emphasis on carbon monoxide gas sensor. This review also focuses the challenges faced by flexible devices, offers the most recent research on paper-based gas sensors and pays special focus on various sensing materials and fabrication techniques.

To get the better insight into opportunities for future improvement, a number of research papers based on sensors were studied and realized the need to design carbon monoxide gas sensor. A number of parameters were then gone through to decide the flexibility parameter to be considered for design purposes. This review also focuses on the challenges faced by flexible devices and how they can be overcome.

It has been shown that carbon monoxide gas, being most contaminated gas, needs to be fabricated to sense low concentration at room temperature, considering flexibility as an important parameter. Regarding this parameter, some tests must be done to test whether the structure sustains or degrades after bending. The parameters required to perform bending are also described.

Due to inherent limitations of conventional silicon-based technology, now-a-days attention is paid towards flexible electronics to design low-cost, high-sensitivity devices. A number of research articles are provided in the literature concerning gas sensing for different applications using several sensing principles. This study aims to provide a comprehensive overview of recent developments in carbon monoxide gas sensors along with the design possibilities for flexible paper-based gas sensors. All the aspects have been taken into consideration for the fabrication, starting with paper characterization techniques, various sensing materials, manufacturing methodologies, challenges in the fabrication of flexible devices and effects of bending and humidity on the sensing performance.