ZnTe/GaAs(2 1 1)B heterojunction valence band discontinuity measured by X-ray photoelectron spectroscopy

Thin ZnTe layers were grown by molecular beam epitaxy on single crystal GaAs(2 1 1)B substrates. Reflection high energy electron diffraction monitored the deoxidation of substrate and entire growth process. Valence band offset was calculated with X-ray photoelectron spectroscopy. Also interface formation of the ZnTe/GaAs was studied. Analysis shows that interface is abrupt and calculated valance band offset is 0.25 ± 0.1 eV and indicates type I alignment. The experimental result agrees well with the theoretical predictions involving interface dipole effect as well as electron affinity rule.

Research highlights▶ Valence band offset of GaAs/ZnTe is found to be 0.25 ± 0.1 eV. ▶ Alignment is type I. ▶ No indication of intermixing was observed at the interface. ▶ Strain does not seem to affect the value found for VBO.