Enhanced Band Edge Luminescence in GaAs with Sulfur Passivation

Abstract

In this work, we perform a sulfur chemical passivation on GaAs substrate, which leads to a change in the photoluminescence (PL) owing to a reduction of surface states. By varying the reaction time of passivation, we can modify the chemical bonds of the GaAs surface and reduce the surface depletion region thickness, which strongly affects the emission efficiency of the GaAs band edge. Based on systematic PL measurements and energy band model with surface states, the sulfur passivation also enhances the number of free and bound excitons. Therefore, sulfur passivation is important to improve the performance of GaAs-based optoelectronics devices.