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arXiv · 2608.27013

Atomic-scale composition of the ternary III-V semiconductor (Al,Ga)Sb visualized by cross-sectional scanning tunneling microscopy

Hitesh Kumar·Vladimir Kaganer·Zijin Lei·Rüdiger Schott·Werner Wegscheider·Stefan Fölsch
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Abstract

Cross-sectional scanning tunneling microscopy at 5 K is used to investigate cation mixing in (Al,Ga)Sb layers grown by molecular beam epitaxy, via direct atom counting at the (1-10) and (110) cleavage planes. Electronic contrast between Al and Ga surface cations enables statistical analysis of the metal sublattice along the non-equivalent <110> directions within the zincblende (001) surface and along the [001] growth direction. The cation distribution is found to be random both along the growth direction and within the growth plane, with no evidence of long-range order or anisotropic growth kinetics; notably, the mean numbers of consecutive cations of the same type along the two in-plane directions are equal, possibly due to statistical averaging over randomly distributed subsurface cations. The results are compatible with either strain-mediated interactions during cation incorporation at the growth front or ideal, uncorrelated cation mixing. Overall, the examined (Al,Ga)Sb alloy shows an exceptionally high degree of atomic-level homogeneity.

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Hitesh Kumar, Vladimir Kaganer, Zijin Lei, Rüdiger Schott, Werner Wegscheider, Stefan Fölsch. 2026-08-27. Atomic-scale composition of the ternary III-V semiconductor (Al,Ga)Sb visualized by cross-sectional scanning tunneling microscopy. https://arxiv.org/abs/2608.27013

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