Papers by Keyword: InAs

Abstract: The Indium Gallium Arsenide (InGaAs) based MOSFETs have been widely used in the research of high-speed devices with higher frequency. It has some application in the designing areas of power amplifiers. The InGaAs mainly have greater electron mobility and the lesser band gap in their compound makes them more suitable for developing high-speed devices. The Indium Gallium Arsenide compound-based MOSFETs are designed using the source/drain grown on a passive layer of Indium Phosphide substrate. This helps in reducing the power budget of the MOSFET and thereby reduces source and drain resistance. The re-grown layers over the bulk have serious issues such as parasitic capacitance and greater electrical field at the terminals of the gate along with the drain terminal. This results in a larger leakage current along with the terminals and thereby induces the degradation of the frequency of the application amplifiers. The high-ƙ dielectric along the gate terminal makes the device immune to leakage current for lesser frequency applications. The optimum material for the dielectric may be Hafnium (IV) Oxide – HfO₂ which has been used as a sidewall in the proposed InGaAs MOSFET design. The device simulation was carried out in a way to evaluate the characteristics of the proposed designs. The results were submissive to the conventional MOSFETs in terms of output capacitance over the source and drain terminals, leakage current in the drain terminal, and improved frequency parameters. The results also suggested that the sidewall design over the gate terminal constitutes the frequency improvement without losing the power and current characteristics.

Abstract: The results of the presented studies demonstrate the possibility of using two and three component solid solutions, based on elements of the A3B5 groups, as thin barrier layers to cover an array of structured InAs quantum dots for photoactive heterointerfaces of solar energy. When using three-component solid solutions for QD barrier layers, a decrease in the thermionic generation in the near infrared spectrum and a decrease in the dark current of the heterointerface are obtained.

Abstract: The process of GaAs and InAs substrates high-temperature annealing under the Langmuir evaporation conditions is studied by Monte Carlo simulation. The temperature range of gallium arsenide and indium arsenide congruent and incongruent evaporation are determined. It was demonstrated that the congruent evaporation temperature T_c is sensitive to the vicinal surface terrace width. The decrease of the terrace width results in a decrease in the congruent evaporation temperature. The Ga and In diffusion lengths along the (111)A and (111)B surfaces at congruent temperatures are estimated. The surface morphology transformation kinetic during high-temperature annealing is analyzed.

Abstract: At present, the performance enhancement for Si-based transistors can no longer be guaranteed due to intrinsic mobility issues. The considerably higher electron mobility of III-V compound semiconductors (e.g. InGaAs, InAs, InSb) has led to renewed interest and a following phase in the development of future transistors for the 7-5 nm technology node [1].

Abstract: Amorphous InAs films are deposited on substrates of quartz glass by RF magnetron sputtering technique in different gas ambient. We present a systematic study of the affects of the sputtering parameters on the chemical composition. Amorphous InAs (a-InAs) films have been achieved at higher working pressure when the substrate temperature and RF power are increased respectively. The films composition is controlled by transport phenomena of sputtered atoms from the target to the substrate and by substrate surface dynamics. We study how to improve the sputtering parameters in order to obtain stoichiometric a-InAs films.

Abstract: The growth details of strained GaAsSb layers on GaAs(001) substrates were studied by reflection high energy electron diffraction (RHEED) beam intensity oscillations as a function of both substrate temperature and Sb/As flux ratio. Both the RHEED intensity and RHEED oscillation cycles are reduced with decreasing substrate temperature and Sb/As flux ratio. InAs QDs with high dot density, small dot size and narrow size distribution have been achieved on strained GaAs / GaAsSb buffer layer. The average lateral size of dots shows a trend toward to smaller size and dots’ density shows a trend toward to higher density as the surface Sb composition increasing. The QDs with higher density and smaller size distributions at high Sb composition, indicates that the Sb plays an important role in the dot formation under this growth condition. The lattice mismatch of InAs layer with the GaAsSb buffer layer is reduced with increasing of Sb composition in the GaAsSb interlayer. This result indicates that the density, size and size distribution of self-assembled quantum dots (QDs) can be controlled through the manipulation of the Sb-mediated strain field in the lattice mismatched system.

Abstract: Using density functional theory, we have studied surface structural and electronic properties of sulfur adsorption on As-terminated and In-terminated InAs(001) surfaces with the coverage (Θ) of 0.5ML and 1ML. Based on adsorption energy calculations, we found that at Θ=0.5ML, S adatoms preferred to replace the As atoms at As-terminated InAs(001)(2×1) surface. For 1ML S adsorption on InAs(001)(2×1) surface, the most stable adsorption geometry is S-S dimers covered on the In-terminated surface. This result is different from that for 1ML S adsorption on GaP(001) and InP(001) surfaces, and it is consistent with the experimental results. The electronic band structure analysis showed that the surface state density around the Fermi level was considerably diminished for 0.5ML S adsorption on As-terminated InAs(001)(2×1) surface at substitution site. The surface state density of S-S dimer adsorption on In-terminated (2×1) surface was strengthened due to one excess valence electron on the surface.

Abstract: InP and InAs quantum rods were synthesized via the reactions of monodispersed indium droplets with phosphide or arsenide ions, respectively. In these reactions indium droplets, which do not act as a catalyst but rather as a reactant, are completely consumed. For the synthesis of InP and InAs quantum rods with a narrow size distribution, a narrow size distribution of indium particles is required because each indium droplet serves as a template to strictly limit the lateral growth of individual InP or InAs nanocrystals. Free-standing InP (130 Å diameter and 870 Å length) and InAs (180 Å diameter and 745 Å length) quantum rods without residual metallic catalyst at the rod tip were synthesized from the diluted transparent solutions of metallic indium. Both kinds of synthesized nanorods are in the strong confinement regime since the Bohr diameters of InP and InAs are 200 and 700 Å, respectively.

Abstract: The structural and photoluminescence (PL) properties of the InAs quantum dots (QDs) grown on a combined InAlAs and GaAs strained buffer layer have been investigated by AFM and PL measurements. The dependence of the critical thickness for the transition from 2D to 3D on the thickness of GaAs layer is demonstrated directly by RHEED. The effects of the introduced-InAlAs layer on the density and the aspect ratio of QDs have been discussed.

Abstract: We report effects of the size and the energy state distribution on the electrical and optical properties in self-assembled InAs quantum dots. The results of characteristics measured using atomic force microscopy, photoluminescence and dark current are analyzed by way of a simulation assuming a Gaussian distribution in size and related energies. The samples investigated in this study are InAs/GaAs quantum dot infrared photodetector structures with an AlGaAs blocking layer grown by molecular beam epitaxy at different growth modes.