Photoemission in Thin-Film Metal-SiOx-CdSe and Metal-SiOx-Metal Contacts

Abstract

Photoemission from vapor‐deposited CdSe and metal electrodes into vapor‐deposited silicon monoxide films has been used to determine the barrier heights at the interface. For the CdSe‐SiO_x interface, a threshold energy of 4.8 eV is determined. Higher values of threshold energy are found for photoemission from gold into silicon monoxide, then from aluminum, indicating that the photocurrent is carried by electrons. In addition, the μτ product of electrons in the insulator has been determined by studying the photocurrent‐voltage dependence; μτ = 2.1×10⁻¹¹ cm²/V. This value is two orders of magnitude less than the results obtained for thermally grown SiO₂. The presence of residual space charge with no applied field is observed and the effect of this space charge on the photocurrent is discussed.