Electronic Structure and Optical Properties ofGaAs1-xBi

Abstract

A first-principles study has been performed to investigate the structural and electronic properties of theGaAs1-xBixsystem. The simulations are based upon the generalized gradient approximation (GGA) within the framework of density functional theory (DFT). Calculations are performed to different Bi concentrations. The lattice constant ofGaAs1-xBixincreases with Bi concentration while the alloy remains in the zinc-blende structure. The band gap ofGaAs1-xBixclearly shrinks with the Bi concentration. The optical transition of Bi dopant in GaAs exhibits a red shift. Besides, other important optical constants, such as the dielectric function, reflectivity, refractive index, and loss function also change significantly.

Accurate Electronic, Transport, and Bulk Properties of Zinc Blende Gallium Arsenide (Zb-GaAs)

“…It has a high electron mobility and a small dielectric constant; GaAs is extensively utilized in high temperature resistance, ultrahigh frequency, low-power devices and circuits. 2 Gallium arsenide crystallizes in zinc-blende structure; many experiments and theoretical works established that it has a direct band gap. Several experimental reports dealt with the room temperature band gap of the material.…”

Stretching the Equilibrium Limit of Sn in Ge1–xSnx Nanowires: Implications for Field Effect Transistors

“…Alloying group IV semiconductors, such as Ge or Si with group IV metals such as Sn, can lead to a direct bandgap semiconductor. − Theoretically, increasing the amount of Sn in bulk Ge results in a direct bandgap at a Sn concentration between 6.5 and 25 atom %, an inverse semimetallic bandgap when Sn is >25 atom %, and an inverse spin–orbit split-off at a Sn content between 45 and 85 atom % . Although a direct bandgap can be achieved in Ge 1– x Sn x alloy for Sn content as low as x = 0.06, a certain degree of Γ–L mixing is observed for Sn contents in the region 0.06 < x < 0.1. , The drive to incorporate high Sn concentrations ( x > 0.1) in Ge 1– x Sn x alloy nanowires can be partly attributed to the presence of this band-mixing at lower Sn content Ge 1– x Sn x alloys. − Recent theoretical calculations have also supported that the indirect-gap to direct-gap transition proceeds via the continuous transition–with increasing x . , The optical and optoelectronic properties of an alloy can be influenced by the alloy composition, as demonstrated both theoretically and experimentally. − A definitive transition to a direct bandgap is required, with large enough Sn incorporation, for the use of Ge 1– x Sn x in efficient optoelectronic devices, such as photodiodes and photodetectors and photonic devices without the need for any external force such as induced strain. , …”