Abstract: The effect of P₂S₅/NH₄OH treatment on the (100) surface of GaAs was studied by X-ray photoelectron spectroscopy (XPS),Auger electron spectroscopy (AES) and photoluminescence (PL).The results show that after passivation the native oxide of GaAs Surface is completely removed and a passivation layer mainly composed of As-Sand Ga-Sbonds forms on the sample surface,and prevents the adsorption of oxygen. This concluson has been supported by results of PL experiments.The PL intensity and its contrast obtained on GaAs surface depend on the surface recombination and they are controlled by passivation. The results of PL experiments show the reduction of surface recombination and of the density of surface states P₂S₅/NH₄OH treatment is more stable than the others,such as Na₂S.

Key words: GaAs, P₂S₅/NH₄OH, Passivation