PREPARATION AND TRANSPORT PROPERTIES OF EPITAXIAL HGTE FILMS

Highly perfect, epitaxial HgTe films have been successfully deposited on semi-insulating CdTe substrates using vapor phase epitaxial techniques. This report describes the preparation of these films and also a number of electrical measurements which were performed over the temperature range 4.2-300°K in order to characterize these thin semimetal layers. It was found that the electrical properties were considerably complicated by the presence of cadmium which diffused from the substrate during film growth. Nevertheless, apparent electron mobilities greater than 105 cm2 V sec and apparent electron densities about 2 × 1015 cm-3 were encountered. Strong quantum oscillations were observed in the magnetoresistance at 4.2°K which represents the first observation of the Shubnikov-de Haas effect in a thin film of any material. Also at 4.2°K, nonohmic conduction was observed at electric field strengths greater than about 5 V cm. Evidence was obtained to suggest that this behavior was due to a warm electron distribution and therefore a field dependent electron mobility. © 1969.