Growth mode of Bi and Sb layers on GaAs(110) and InP(110)

Abstract

Abstract The growth mode of thin Bi and Sb overlayers on GaAs(110) and InP(110) substrates was studied in ultra high vacuum (UHV) for room temperature (RT) deposition and subsequent annealing. Analysis was performed by means of LEED, Raman spectroscopy and Auger electron spectroscopy (AES). For Bi deposited on GaAs(110), three different modifications are observed with increasing coverage. The first two monolayers grow epitaxially. On top of this layer Bi grows in a pseudocubic orientation. At coverages above 8 ML, islands of the bulk-like D 3d crystal structure appear. Upon annealing the epitaxial Bi layer and the bulk-like Bi modification are stable up to 575 K, the highest annealing temperature investigated, whereas the pseudocubic Bi modification desorbs around 540 K leaving an epitaxial monolayer behind. For Bi on InP(110), only two modifications are observed. An epitaxial monolayer is formed at first, but directly followed by facets of Bi islands of the D 3d structure, with the hexagonal axis parallel to the [001] direction in the InP(110) surface. For large coverages these facets are thermally stable. For Sb deposition on GaAs(110) and InP(110), three Sb modifications have been reported previously: with increasing coverage an epitaxial monolayer, amorphous Sb and the crystalline D 3d Sb have been observed. Upon annealing the amorphous Sb is transformed into crystallites of a pseudocubic modification around 400 K. The crystallites desorb above 475 K, whereas the epitaxial and the D 3d Sb modifications are stable up to at least 575 K.