Nonmagnetic-semimagnetic semiconductor heterostructures: Ge-Cd1-xMnxTe(110)

Synchrotron-radiation photoemission studies of heterovalent heterojunctions involving Ge and Cd1-xMnxTe alloys (x=0, 0.35, and 0.60) were performed on interfaces prepared in situ by Ge deposition on cleaved (110) semimagnetic semiconductor surfaces. The valence-band offsets ΔEv were obtained with consistent results through a nonlinear least-squares fit of the interface valence-band emission in terms of a superposition of valence-band spectra for the individual semiconductors, and with a more conventional method utilizing the Te 4d and Ge 3d core-level emission. We find valence-band offsets ΔEv=0.80-0.83 eV largely independent of semimagnetic composition and band gap. In the framework of the linear models of semiconductor heterojunction behavior, this result would indicate that CdTe-Cd1-xMnxTe heterojunctions will follow the common anion rule.