Molecular beam epitaxy growth of PbSe on BaF2-coated Si(111) and observation of the PbSe growth interface

Epitaxial growth of PbSe/BaF2/CaF2 heterostructures was carried out by mole cular beam epitaxy (MBE) on Si(lll) wafers. Successful transfer of 3-mu m-t hick PbSe epilayers was accomplished by bonding the MBE-grown samples face down to polished copper plates followed by the removal of the silicon subst rate by dissolving the BaF2 buffer layer in water. High-resolution x-ray di ffraction measurements demonstrated that the PbSe epilayer maintained high- crystalline quality after transfer. In addition, optical Nomarski character ization of the exposed growth interface showed sets of parallel straight st ep lines consistent with glide of dislocations in the primary {100}[110] gl ide system. Such features are evidence of the large thermal expansion misma tch strain that occurred in these layers. (C) 1999 American Vacuum Society. [S0734-211X(99)03803-2].