PHOTOELECTROCHEMICAL ETCHING OF INAS

Photoelectrochemical etching of n-InAs (E(g) = 0.36 eV) is demonstrate d. Although the concentration of thermally generated minority carriers and saturation current are high compared to larger bandgap semiconduc tors, photocurrent to dark current ratios as high as 4:1 were obtained at low temperature (2-degrees-C) and at potentials near the flatband potential. A surface film primarily composed of arsenic oxide was form ed during oxidative decomposition of the semiconductor and plays a rol e in the rate of dissolution and in the current-voltage response. In 0 .2M H2SO4, 6 electrons per InAs were involved in the oxidation dissolu tion, while only 4 electrons per InAs were found in 0.2M HCl because o f the formation of In(I)-chloride species.