Buildup of III-V-compound semiconductor heterojunctions: Structural and electronic properties of monolayer-thick III-V overlayers on III-V substrates

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Abstract
We report an extensive study of the first stages of the buildup by molecular-beam epitaxy of III-V-compound semiconductor heterojunctions (AlAs, InAs, and GaAs with each other, and GaAs/GaP and InAs/InP). Surface-sensitive techniques have been applied in situ, first to yield information on the geometry and crystal structure of monolayer-thick overlayers of a III-V compound grown upon another III-V substrate. For atomically well-defined heterointerfaces, the buildup of the electron states at the interface has then been analyzed. In these cases, with respect to the vacuum level, the substrate band structure remains stationary, and the overlayer surface- and bulk-derived electron states appear at the position they have in the bulk overlayer material, within a ±0.1 eV accuracy limit. The band offsets that we deduce are in good agreement with the electron-affinity rule and with recent experimental and theoretical data.