Two-dimensional nucleation at stacking fault during InP microchannel epitaxy

Abstract

An atomic force microscopy (AFM) is used to study the origin of a strong step source in InP microchannel epitaxy (MCE). The AFM images showed that two-dimensional nuclei were frequently generated at a stacking fault (SF). It was found that the shape of the two-dimensional nuclei was not circular but bow-like, whose chord coincides with the line of the SF and aligns in the 〈0 1 1〉 direction. The large radius of curvature of its arc and the large contact angle with SF allow the nucleation to occur at a very low critical supersaturation. As a result, two-dimensional nucleation becomes a major source supplying the growth steps when SF exists even under a very low supersaturation usually employed in MCE.