Investigation of oxide growth and stability on n-GaAs and n-InP by coupling transient photocurrent and surface analysis

Investigation of oxide chemistry and reactivity of III-V semiconductors has been undergone with an electrochemical approach coupled with surface analy sis. Growth and stability of anodic oxides obtained on n-GaAs and n-InP was investigated with potensiostatic mode under illumination at pH 9. For the two compounds, the transient photocurrent. the recovery of the photocurrent and XPS analysis were performed in the same conditions. InP and GaAs prese nt very different behaviours, which are linked to the stability of the oxid ised interface. InP evidences a thin, stable and electrically blocking oxid e film, while GaAs exhibits a thicker, unstable and porous oxide layer. Thi s work point out that XPS analysis has to be coupled with in situ technique s as transient photocurrent, to understand accurately the oxide growth mech anism. (C) 2001 Elsevier Science B.V. All rights reserved.