{100} Surfaces of III–V, II–VI, and I–VII Compound Semiconductors with Zincblende Structure

Abstract

In the bulk of zincblende-type compound semiconductors, {100} planes are alternately occupied by cations and anions. Ideally terminated {100} surfaces would thus consist of either cations or anions and each surface atom would possess two dangling bonds. Clean (001) surfaces of such compounds are, however, not ideally terminated but rather exhibit a number of different reconstructions and compositions. The mechanism, which is basically responsible for the reconstructions, is the reduction of the number of dangling bonds by dimerization of surface atoms. Due to their large difference in energy, dangling bonds will be completely occupied at surface anions but empty at surface cations. Finally, missing dimers account for the respective number of electrons needed for the dimer bonds and the filled dangling bonds at surface anions. The intrinsic surface band structures are semiconducting but the Fermi level is pinned close to mid-gap position by extrinsic defects.