ORGANOMETALLIC VAPOR-PHASE EPITAXY OF HG1-XCDXTE ON (211)-ORIENTED SUBSTRATES

Hg1-xCdxTe layers have been grown by organometallic vapor-phase epitaxy at 350-degrees-C on {211}-oriented substrates, including CdTe, (CdZn)Te, and GaAs, with the emphasis on lattice matching for improved structural quality films. Characterization included optical microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, and detailed field and temperature Hall measurements. The (211)B-oriented epilayers combine the structural quality of (100) including the absence of twinning with the flat topography of (111)B-oriented films. The crystal quality improved to that of the substrate with the closer lattice matching of (CdZn)Te, the mismatch taken up with lattice inclination on the high step density surface. A tighter control of the substrates' Zn content than exists at present is required for ultimate lattice matching to Hg0.2Cd0.8Te. As-grown Hg1-xCdxTe on (CdZn)Te (211)B substrates is p type with carrier levels in the 1-6 x 10(16)-cm-3 range for compositions greater than 0.20 and with no indication of mixed conduction behavior due to inversion layers or growth-related surface or interface layers.