Ce4+: a new etching agent for cadmium telluride

Cadmium telluride (CdTe) has been etched for the first time in a 2M H2SO4 solution in the presence of Ce4+. The etching rates have been obtained by means of step measurements. They are proportional to the Ce4+ concentration and to the dipping time and are close to etching rates obtained for III-V compounds under the same conditions. The etching rates show no decrease with time in the concentration range studied (10-4M-10-1M) even for large steps (several μm). Etching rates up to 0.1 μm/min have been obtained, which can be increased by a factor of about 10 by ultrasonication. The evolution of composition of the sample surface has been investigated by means of X-ray photoelectron spectroscopy (XPS) analysis. Elemental tellurium-rich, oxide-free surfaces are obtained after etching in the presence of Ce4+. (author)