Stoichiometry loss induced by ionic bombardment of InP surfaces: A challenge for electrochemistry combined with XPS

Abstract

Indium phosphide (InP) surfaces are greatly affected by ionic bombardment. We investigate the resulting surface perturbation through the use of the complementary analytical techniques of electrochemistry and X-ray photoelectron spectroscopy (XPS). Following bombardment, modifications to the surface were identified by a reduction in the dark open circuit potential in comparison to the pristine state. Through XPS studies, it was found that the sputtered surface was enriched with a metallic-like In contribution, which oxidized upon exposure to air. Cyclic voltammetry measurements confirmed this observation, with initial cathodic features related to an oxidized metallic In-enriched layer on the InP surface. Repeated cyclic voltammetry experiments resulted in the formation of a more In-rich overlayer due to a specific oxidation/reduction phenomenon. This behavior is very similar to that obtained by cathodic decomposition on InP surfaces.

Keywords

• Indium phosphide
• XPS
• Electrochemistry
• Argon bombardment