In-Situ Characterization of Compound Semiconductor Surfaces by Novel Photoluminescence Surface State Spectroscopy

The recently proposed novel photoluminescence surface state spectroscopy (PLS 3 ) technique is applied for in-situ , non-destructive and contactless characterization of variously processed surfaces of GaAs, InP and InGaAs. Chemically etched, anodized and passivated surfaces, as well as the original as-received surface, give rise to U-shaped surface state density distributions with characteristic charge neutrality energy levels, E HO , which is consistent with the disorder induced gap state (DIGS) model. Annealing of as-received surfaces in hydrogen ambient leads to formation of discrete levels, possibly due to escape of As or P atoms. The effectiveness of a new UHV-based passivation scheme for InGaAs using an ultrathin MBE Si interface control layer (ICL) is also confirmed.