Photoluminescence and Lifetime Measurement for the Excitation and Temperature Dependence of Carrier Relaxation in III-V Semiconductors

Abstract

Researches in the field of III-V semiconductor photonic devices have initiate applications in a number of disciplines including lighting, optical communications and biomedical engineering. One of the limiting factors for getting better the photonic devices is the carrier relaxation time. This is the time obligatory for energetic carriers to cool to the edge of their particular bands in a bulk semiconductor material, or to the bottom of a well throughout inter- and intra-sub-band spreading in a heterojunction structure. From these lower energy states, they can afterwards recombine radiatively in photonic devices. This study exploited the nonlinear optical practice of frequency up conversion to complete time-resolved luminescence spectroscopy on epitaxial bulk GaAs samples to analyse carrier relaxation times in each as a function of excitation irradiance and temperature of the sample. There is no electrons and defect energy level in the energy curve for p-type samples. In this study, we focus on the recombination process of yellow-luminescence, which causes the decrease in emission efficiency. The variation of yellow-photoluminescence spectrum shape and intensity, which is caused by occupation YL centers by electrons and thermal activation processes of energy level transitions of electrons by phonon collision in GaAs. The measurement model explains the dependence of the PL intensity on excitation intensity, as well as the PL lifetime and its temperature dependence. We demonstrate that time-resolved PL measurements can be used to find the concentrations of free electrons and acceptors contributing to PL in p-type semiconductors.