Correlation between defect concentration and carrier lifetime of GaAs grown by molecular beam epitaxy at different temperatures
Journal
Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Journal Volume
40
Journal Issue
11
Pages
6239-6242
Date Issued
2001
Author(s)
Abstract
A pump-probe study of GaAs grown by molecular beam epitaxy at low temperatures (LT-GaAs) is performed. Ultrashort carrier lifetimes of the as-grown LT-GaAs increase from <0.13 ps (measurement limitation) to 1.8±0.2 ps as the growth temperature is increased from 200°C to 320°C. The carrier lifetime was found to be approximately inversely proportional to the antisite defect concentration. This trend is found to be in reasonably good agreement with the Schokley-Read-Hall model. The decreasing trend in the amplitudes of continuous-wave and transient reflectivities (ΔR/R) as a function of the growth temperature for the LT-GaAs is explained as an induced absorption caused by dense arsenic antisite defects. The sign of the transient ΔR/R reversed for LT-GaAs grown at 200°C. This is tentatively attributed to the band gap renormalization effect.
Subjects
Carrier lifetime; Defect; LT-GaAs; MBE; Photo-reflectivity; Pump-probe; Ultrafast
Other Subjects
Carrier concentration; Carrier mobility; Energy gap; Hot carriers; Low temperature operations; Mathematical models; Molecular beam epitaxy; Optical properties; Point defects; Solid state lasers; Spectroscopy; Ultrafast phenomena; Band gap renormalization effect; Carrier lifetime; Defect concentration; Dense arsenic antisite defect; Low temperature gallium arsenide; Optical reflectivity spectroscopy; Pump-probe; Shockley-Read-Hall model; Time resolved photoreflectivity; Semiconducting gallium arsenide
Type
journal article