Raman spectroscopy of PLEE (pulsed laser evaporation and epitaxy)-grown Cd1−xMnxTe films on (111) GaAs and (001) InSb

Abstract

Raman light-scattering measurements have been used to characterize Cd1−xMnxTe (CMT) epilayers, 0.6–1.7 μm thick, deposited using pulsed laser evaporation and epitaxy (PLEE) on (111) GaAs and (001) InSb. Under outgoing resonance Raman conditions with a photoluminescence peak thought to be due to neutral acceptor-bound magnetic polaron emissions, five to seven overtones in various combinations of the "CdTe–like" and "MnTe–like" longitudinal optic phonon modes have been seen in six samples of CMT–GaAs at 14 K. This extreme degree of enhancement attests to the high quality of the PLEE-grown epilayers. The combination of the II–VI semiconductor CdTe and the III–V substrate InSb in a heterojunction is of particular interest because of the nearly perfect lattice match (within 0.05% at 300 K) and the large difference in the band gaps (1.45 and 0. 18 eV), which promise interesting device applications. Measurements of Raman scattering for CdTe deposited on n- and p-type (001) InSb were performed. Films with an intermediate CdTe buffer layer show better Raman characteristics than those produced without the buffer layer or with a Cd overpressure.