Ionization energy of acceptors in As-doped HgCdTe grown by molecular beam epitaxy

The p-type activation of arsenic (As) in (211)B mercury cadmium telluride (HgCdTe) grown by molecular beam epitaxy (MBE), with different compositions covering the 3-5 and 8-14 mu m atmospheric transmission windows and after annealing at 300 degrees C is reported. The composition and thickness of the MBE layers were determined from Fourier transform infrared transmission measurements at room temperature. The ionization energies of shallow accepters related to As in MBE HgCdTe layers with different Cd compositions have been obtained by fitting variable temperature Hall measurement results to a two-band nonparabolic Kane model. The results indicate that As incorporated during the MBE growth can be activated to provide a shallow acceptor level in MBE HgCdTe and the ionization energy of the As acceptor decreases with decreasing Cd composition, in agreement with the theory. (C) 1998 American Institute of Physics.