MECHANISMS OF MOLECULAR-BEAM EPITAXIAL-GROWTH OF (001) HGTE

We report on an investigation of the growth mechanisms of HgTe using a combination of reflection high energy electron diffraction (RHEED) an d scanning tunneling microscopy (STM). The experiments were carried ou t on untilted (001) CdTe substrates. Growth rates were determined from RHEED intensity oscillations of the (00) specular spot reflection. Th e amplitude of these oscillations decrease with increasing substrate t emperature. Above 178 degrees C no RHEED oscillations could be measure d. Upon reducing the sample temperature below 178 degrees C these osci llations could again be observed. This cyclic behavior could be induce d several times for each sample, indicating a reversible change in the growth mechanism. In order to correlate the surface structure with RH EED observations, several samples have been investigated with STM. Thu s, it could be confirmed that a temperature dependent transition occur s during the MBE growth of HgTe from the island growth mode below the critical temperature of 178 degrees C to a step how mode above this te mperature. (C) 1996 American Institute of Physics.