Backreflection x-ray standing waves and crystal truncation rods as structure probe for epilayer–substrate systems

Abstract

Backreflection x-ray standing waves (BRXSW) and crystal truncation rod (CTR) scatterings have been used to probe the structure of heteroepitaxial CaSrF2 crystals on GaAs(111)B substrate. Coupled with the film-thickness information obtained from x-ray Fresnel reflectivity data, the combined x-ray standing wave and BRXSW data suggest one or both of the F and As layers missing from the heteroepitaxial interface. The CTR data support a missing F layer and interface (Ca, Sr) atoms occupying the T sites on GaAs(111) surface.