Characterization of charged defects in Cd_xHg_(1-x)Te and CdTe crystals by electron beam induced current and scanning tunneling spectroscopy

摘要

A correlative study of the electrically active defects of CdxHg1-xTe and CdTe crystals has been carried out using a scanning electron microscope/scanning tunneling microscope (SEM/STM) combined system. Charged structural and compositional defects were revealed by the remote electron beam induced current (REBIC) mode of the scanning electron microscope. The electronic inhomogeneities of the samples were analyzed with nm resolution by current imaging tunneling spectroscopy (CITS) measurements, which showed the existence of built-in electrostatic barriers as well as local variations of the surface band gap in the defect areas imaged by REBIC.