Wurtzite CdS on CdTe grown by molecular beam epitaxy

Abstract

Growth of single crystal wurtzite cadmium sulfide on CdTe(111)B substrates has been achieved using molecular beam epitaxy. Reflection high-energy electron diffraction (RHEED) indicates smooth surface morphology for several hundreds of nanometers after nucleation. X-ray diffraction measurements confirm the crystalline orientation to be [0001] in the growth direction. X-ray photoelectron spectroscopy (XPS) indicates mostly stoichiometric CdS layers and the existence of a reaction at the interface. Sulfur incorporation into CdTe for various S fluxes has been investigated by Auger electron spectroscopy (AES). High-resolution TEM images of the interface between such epilayers were recorded. During the growth In was used as an in-situ dopant. The concentration and uniformity of In was determined by secondary ion mass spectrometry. Indium profiles were obtained for concentrations ranging from 5 × 10¹⁷ to 1.4 × 10²¹ cm⁻³. The experimental concentration agrees well with the variation expected from the In flux.