Identification of short-range ordering motifs in semiconductors
Lilian Vogl, Shunda Chen, Peter Schweizer, Xiaochen Jin, Shui-Qing Yu, Jifeng Liu, Tianshu Li, Andrew M. Minor
Abstract
Chemical short-range ordering is expected to be a key factor for tuning the electronic structure of semiconductors. However, experimental evidence of short-range ordering is still lacking due to the challenge of characterizing atomic-scale ordering motifs. Here, we determined the presence of short-range order in a ternary GeSiSn semiconductor system using advanced energy-filtered four-dimensional scanning transmission electron microscopy and large-scale atomistic models generated by a machine learning neuroevolution potential of first-principles accuracy. This approach revealed preferred ordering of different atomic species with the dominant occurrence of Si-Ge-Sn triplets. Our findings not only confirmed the presence of short-range order but also directly revealed the actual atomic structure, demonstrating the potential for informed atomic order-based band engineering as a third degree of freedom beyond composition and strain tuning.