Ce⁴⁺: a New Etching Agent for Cadmium Telluride

Abstract

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 ( 10-4 M-10-1 M) even for large steps (several µ m). Etching rates up to 0.1 µ m/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+.

Reduction mechanisms of different oxidizing agents at diamond surfaces

“…''Electroless'' oxidation has been widely described on III-V and II-VI semiconductor (SC) interfaces. These works showed that using oxidizing agents with standard potentials close to the valence band (VB) position of the material, the reduction of the oxidizing agent by holes injection and the oxidation of the SC take place simultaneously on the same surface [19][20][21][22][23]. In a previous work, the ''electroless'' oxidation of as-deposited polycrystalline boron-doped diamond (BDD) films, using four different oxidizing solutions at room temperature, Ce 4+ , MnO 4…”

Electroless Oxidation of Diamond Surfaces: Relevance of Concepts Developed for Classical SC Electrochemistry

“…We investigate the "electroless" oxidation of asdeposited polycrystalline BDD films in oxidizing solutions at room temperature. "Electroless" oxidation has been widely studied on III-V and II-VI semiconductor (SC) interfaces [5][6]. These works showed that using oxidizing agents with very positive standard potentials (V°ox/red) close to the valence band (VB) position of the material, the reduction of Ox + by holes injection in the Valence Band and the oxidation of the SC can take place simultaneously on the same surface.…”

“…Current-voltage measurements with Rotating Disk Electrode (RDE) were also performed to study the reduction mechanism of Ce 4+ and Fe(CN) 6 3oxidizing molecules at Diamond surfaces.…”