Surface Modification of CdTe Crystal by Plasma Treatment Using Various Gases

Plasma treatments using various gases have been applied to CdTe(111) surfaces. The induced surface layer composition and morphology were analyzed by X-ray photoelectron spectroscopy and field-emission scanning electron microscopy. He and Ar plasma treatments yielded an approximately stoichiometric surface and morphologies with a pyramidal structure. The surface with the H 2 plasma treatment had ball-like particles and was Cd-rich. Furthermore, the surface with the O 2 plasma treatment was almost oxidized. An Al/CdTe Schottky contact formed on the surface after the He, Ar, and H 2 plasma treatments showed good rectification properties due to elimination of a Te-rich layer.