arXiv subjects

Mohammad Zamani Alavijeh

Publications and source records attributed to Mohammad Zamani Alavijeh.

2 recordsLinked to original sources

arXiv2024

Algorithm-Based Linearly Graded Compositions of GeSn on GaAs (001) via Molecular Beam Epitaxy

The growth of high-composition GeSn films of the future will likely be guided via algorithms. In this study we show how a logarithmic-based algorithm can be used to obtain high-quality GeSn compositions up to 16 % on GaAs (001) substrates via molecular beam epitaxy. Within we demonstrate composition targeting and logarithmic gradients to achieve linearly graded pseudomorph Ge1-xSnx compositions up to 10 % before partial relaxation of the structure and a continued gradient up to 16 % GeSn. In this report, we use X-ray diffraction, simulation, SIMS and atomic force microscopy to analyze and demonstrate some of the possible growths that can be produced with the enclosed algorithm. This methodology of growth is a major step forward in the field of GeSn development and the first demonstration of algorithmically driven, linearly graded GeSn films.

cond-mat.mtrl-sci↗

arXiv2022

Modeling of V graded In(x)Ga(1-x)N solar cells: comparison of strained and relaxed features

The optical properties of V graded InGaN solar cells are studied. Graded InGaN well structures with the indium composition increasing then decreasing in a V shaped pattern have been designed. Through polarization doping, this naturally creates alternating p-type and n-type regions. Separate structures are designed by varying the indium alloy profile from GaN to maximum indium concentrations ranging from 20% to 80%, while maintaining a constant overall structure thicknesses of 100 nm. The solar cell parameters under fully strained and relaxed conditions are considered. The results show that a maximum efficiency of 5.5%, under fully strained condition occurs at x=60%. Solar cell efficiency under relaxed conditions increases to a maximum of 8.3% at 90%. While Vegards law predicts the bandgap under relaxed conditions, a Vegard like law is empirically determined from the output of Nextnano for varying In compositions in order to calculate solar cell parameters under strain.

cond-mat.mtrl-sci↗