Raman Spectroscopy of Anodic Oxide Films on HgTe

Laser Raman spectroscopic measurements of the anodic oxide film formed on HgTe in aqueous olutions reveal the characteristic Raman bands that appear at 422 and 684 cm- '. These bands, which are different from those of crystalline HgTeO3 and TeO2 powders, may be attributed to a complex oxide of HgTe20 ~ or an amorphous oxide of TeO, that might be formed in anodic oxidation. The heating effect on the anodic oxide film due to a focused laser beam is also discussed. Surface passivation of compound semiconductors Cdx Hg,_xTe (CMT) is of considerable importance in their utilization as photoconductive devices. One of the most common methods for surface passivation is anodic oxida-tion (1). In previous papers, the electrochemical reaction and the anodic oxide films of CMT and HgTe have been investigated by using x-ray photoelectron spectroscopy (XPS) and rotating ring-disk electr})de (2-4). Furthermore, there have been a few papers dealing with composition of the anodic oxide (5-7). In recent years, laser Raman scat