Extended X-Ray Absorption Fine Structure Study of Arsenic in HgCdTe

Extended x-ray absorption fine structure (EXAFS) experiments using the As K-edge have been carried out at the European Synchrotron Radiation Facility on two molecular beam epitaxy (MBE) grown arsenic-doped HgCdTe samples. Arsenic (As) is provided by a radio-frequency plasma cell and was incorporated to a level of a few 1018 at·cm−3. Both samples were analyzed as grown and after a high-temperature anneal (410°C/1 h) under saturated mercury pressure. The EXAFS signature of as-grown and annealed samples are strikingly different, indicating a drastic change in the environment of the As atom. In any case, the EXAFS signal originates from at least two different contributions and is found to be dominated by As clusters. The other contribution for as-grown samples comes from tellurium neighbors indicating that As incorporates partially in the (Cd,Hg) site.