Electrical Activation and Electrical Properties of Arsenic Doped Hg(1- x)Cd(x)Te Epilayers Grown by MBE

摘要

The annealing and electrical properties of extrinsic in situ doped mercury cadmium telluride (Hg(1-x)CD(x)Te) epilayers grown by molecular beam epitaxy (MBE) on (211)B CdTe/Si and CdZnTe substrates are studied. The doping is performed with an elemental arsenic source. HgCdTe epilayers of CdTe mole fraction in the range of mid-wavelength infrared (MWIR) are grown at substrate temperatures of 175-185 degrees C. The temperature dependent Hall effect characteristics of the grown samples are measured by the van der Pauw technique. A magnetic field of up to 0.8 T is used in these measurements. The analysis of the Hall coefficient in the temperature range of 40-300 K with a fitting based on a three-band non-parabolic Kane model, a fully ionized compensating donor concentration, and two independent discrete acceptor levels is reported. Both as-grown and annealed samples are used in this study. All of the as-grown samples showed n-type characteristics whereas annealed samples showed p-type characteristics. Activation annealing at different temperatures was performed. Conversion to p-type at lower than conventional annealing temperatures was achieved. Theoretical models are utilized to understand the dependence of the activated arsenic concentration on the annealing temperature.