Donor doping of (211) CdTe epilayers and CdTe/CdZnTe piezoelectric heterostructures by molecular beam epitaxy

Abstract

Shallow indium donors have been incorporated in (211) CdTe and CdZnTe epilayers by molecular beam epitaxy. For this orientation, no Cd overpressure is necessary to incorporate the indium donors. Essentially 100% activation of donors was obtained in the 1016–7×1017 cm−3 concentration range. Electron mobility was 7300 cm2 V−1 s−1 at 40 K for 3×1015 donors cm−3. Transmission electron microscopy shows that the doped (211) CdTe layers have high structural quality. Optical spectra of modulation-doped (211) CdTe/CdZnTe quantum wells show that an electron gas present in a piezoelectric CdTe well produces strong screening of the internal electric field.