Semicoherent growth of BiTe layers on InP substrates by hot wall epitaxy

Abstract

We search for optimum growth conditions to realize flat BiTe layers on InP(111)B by hot wall epitaxy. The substrate provides a relatively small lattice mismatch, and so (0001)-oriented layers grow semicoherently. The temperature window for the growth is found to be narrow due to the nonzero lattice mismatch and rapid re-evaporation of BiTe. The crystalline qualities evaluated by means of x-ray diffraction reveal deteriorations when the substrate temperature deviates from the optimum not only to low temperatures but also to high temperatures. For high substrate temperatures, the Bi composition increases as Te is partially lost by sublimation. We show, in addition, that the exposure of the BiTe flux at even higher temperatures results in anisotropic etching of the substrates due, presumably, to the Bi substitution by the In atoms from the substrates. By growing BiTe layers on InP(001), we demonstrate that the bond anisotropy on the substrate surface gives rise to a reduction in the in-plane epitaxial alignment symmetry.