Atomic layer epitaxy growth of ZnS on (100)GaAs using molecular beam epitaxy system

Abstract

The atomic layer epitaxy (ALE) growth of monocrystalline ZnS is successfully carried out onto (100)GaAs substrates at 185–;200°C by the use of a molecular beam epitaxy system, and the growth mechanism is considered with the results of reflection high energy electron diffraction (RHEED). The ALE growth is performed with alternative irradiations of Zn and S molecular beams. The orientation of the epilayer is 〈100〉 and the epilayer is free from twins. The RHEED patterns suggest that the progress of the growth of ALE-ZnS is based on the alternative change of the surface structures of c(2 × 2)-Zn and (2 × 1)-S. The growth rate per cycle is remarkably dependent on the substrate temperature and the origins of the growth rate variation are presumably due to the temperature dependences of the dissociations of cluster molecules or polyatomic molecules and of sticking coefficients for Zn and S.