Electrical characteristics of As-doped p-type HgCdTe epilayers grown on CdZnTe(211)B substrates by molecular beam epitaxy

We report here the electrical properties of As-doped HgCdTe(211)B epilayers grown by molecular beam epitaxy (MBE) using As-4 as the dopant. It is foun d that though the as-grown As-doped HgCdTe layers are n? type, As can be ac tivated to be a p-type dopant in the HgCdTe(211)B layers after an ex situ a nnealing process. The AS(4) sticking coefficient on the growing HgCdTe surf ace is found to decrease from the order of 10(-2)-10(-4) when the substrate temperature is increased from 165 to 175 degrees C. The hole mobility in A s-doped HgCdTe is calculated by considering seven major scattering mechanis ms: ionized impurity, strain field, polar optical phonon, acoustic phonon, alloy disorder, nonpolar optical phonon, and dislocation scattering. The io nization energies of shallow acceptors related to As in MBE HgCdTe layers w ith different Cd composition have been obtained by fitting variable tempera ture Hall measurement results to a two-band nonparabolic Kane model. (C) 19 99 American Vacuum Society. [S0734-211X(99)03603-3].