Preparation of Bi2Te3 Films by Hot-Wall Epitaxy and Characterization of p-n Junction

Abstract

The deposition of bismuth telluride thin films, as well as of Bi–Sb–Te and Bi–Te–Se ternary alloys by hot-wall epitaxy, has been optimized on various substrates like Si, SiO2 and SiO2/Si. In order to enhance the thermoelectric power, we investigated the electrical conductivity σ, the Hall coefficient RH and the Seebeck coefficient S. The properties of the epitaxial films grown on SiO2 and on SiO2/Si substrates are rather similar whereas for Bi2 (Te1–xSex)3 ternary alloys, the n and p doping is close to the optimum value that can be from bona fide expected. Finally, the study of current–voltage characteristics at room temperature, for a p-Bi2Te3–n-Bi2Te3 junction allowed us to determine various and important parameters (n, Rs, Js and ΦB).