The effect of chemical and in-situ electrochemical etching on the morphology of the mercury cadmium telluride (HgCdTe) surface, prior to growth of the cadmium sulfide (CdS) films, has been examined. The US films have also been characterized using grazing angle X-ray diffraction and optical absorption spectroscopy. Preferential growth of (002) planes of US has been observed on the HgCdTe substrate. The effectiveness of the surface treatment and US growth methodology for passivation of the HgCdTe surface has been examined using capacitance-voltage studies of Au/H-CdTe/CdS/Au devices at 77 K. A negative fixed charge density similar to 10(15)/m(2) was obtained. (c) 2006 Elsevier B.V. All rights reserved.