Orientation independence of heterojunction-band offsets at GaAs-AlAs heterointerfaces characterized by x-ray photoemission spectroscopy

Abstract

We systematically studied the orientation and the growth sequence dependence of the valence‐band offset ΔE_v at the lattice‐matched common anion GaAs‐AlAs interfaces. High quality GaAs‐AlAs heterojunctions were carefully grown on GaAs substrates with three major orientations, namely, (100), (110), and (111)B. The core level energy distance ΔE_CL between Ga 3d and Al 2p levels was measured by in situ x‐ray photoemission spectroscopy. ΔE_CL is found to be independent of the substrate orientation and the growth sequence, which clearly indicates the face independence of ΔE_v. This result suggests that the band lineup at lattice‐matched isovalent semiconductor heterojunctions is determined by the bulk properties of the constituent materials. ΔE_v is determined to be 0.44 ± 0.05 eV.