Metal-CdTe interfaces

Abstract

We discuss the detailed formation of Schottky barriers at interfaces between a range of metals and atomically clean surfaces of CdTe, prepared by cleavage in ultra high vacuum. The microscopic aspects associated with metal induced interface disorder, surface dissociation and interdiffusion of atoms across the interface have been probed by a range of methods including ultra violet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and I-V and C-V methods simultaneously. The mechanisms responsible for Fermi level pinning are considered in detail and the importance of metal induced interfacial defects is emphasized. The modification of the Schottky barriers to vacuum cleaved CdTe is investigated using reactive interlayers, of Al or TeO 2, between the clean CdTe surface and the Schottky contact.