Study of the CdTe/As/Si(111) interface by scanning tunneling microscopy and X-ray photoelectron spectroscopy

The structure of the CdTe/As/Si(111) interface has been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) after desorption of a 5 μm thick CdTe film grown by molecular beam epitaxy. After annealing around 500°C, 2D islands of CdTe remain on the As/Si(111) surface. Both XPS and STM show a coverage of ∼1/4 of a monolayer. STM reveals that islands are not homogeneously distributed, but that a depleted zone exists on top of the step edges. These results agree with a model based on CdAs bonds at the interface to explain the growth of CdTe(1̄1̄1̄)B on As-terminated Si(111).