Extrinsic p-type doping of HgCdTe grown by organometallic epitaxy

Abstract

In this letter, we report on the extrinsic p‐type doping of mercury cadmium telluride (MCT), during growth by organometallic vapor phase epitaxy. Arsine gas in hydrogen was used as the dopant source. The layers were characterized by Hall effect and by resistivity measurements over the temperature range from 20 to 300 K. The acceptor ionization energy was obtained for different doping concentrations from the Hall coefficient data. Its value decreases with doping concentration, and is about 8.5 meV for a doping of 1.1×10¹⁶ cm⁻³. This is a factor of 2 lower than the ionization energy of mercury vacancies, for layers of this (27–30% cadmium) composition and doping level. Annealing at 205 °C for 15 h in a Hg‐rich ambient did not produce significant changes in the measured doping concentration. This indicates that the acceptor level is extrinsic in nature, and that arsenic behaves as a stable acceptor dopant in MCT, grown by organometallic epitaxy.