Correlation between Photoluminescence and Surface-State Density on GaAs Surfaces Subjected to Various Surface Treatments

Abstract

Relationship between band edge photoluminescence (PL) and surface states is rigorously analyzed on computer, using the disorder-induced gap state (DIGS) model, and is compared with experiments on GaAs surfaces subjected to various treatments. It is shown that PL intensity is directly correlated with the effective surface recombination velocity, but is not necessarily directly correlated with the surface-state density ( N ss ) itself. PL enhancement by photochemical oxidation and by Na 2 S deposition is proposed to be due to a fixed negative charge, whereas photochemical treatment in HCl leads to significant reduction in N ss .