2D Lateral Heterojunction Arrays with Tailored Interface Band Bending.

Abstract

Two-dimensional (2D) lateral heterojunction arrays, characterized by well-defined electronic interfaces, hold significant promise for advancing next-generation electronic devices. Despite this potential, the efficient synthesis of high-density lateral heterojunctions with tunable interfacial band alignment remains a challenging. Here, a novel strategy is reported for the fabrication of lateral heterojunction arrays between monolayer Si₂Te₂ grown on Sb₂Te₃ (ML-Si₂Te₂@Sb₂Te₃) and one-quintuple-layer Sb₂Te₃ grown on monolayer Si₂Te₂ (1QL-Sb₂Te₃@ML-Si₂Te₂) on a p-doped Sb₂Te₃ substrate. The site-specific formation of numerous periodically arranged 2D ML-Si₂Te₂@Sb₂Te₃/1QL-Sb₂Te₃@ML-Si₂Te₂ lateral heterojunctions is realized solely through three epitaxial growth steps of thick-Sb₂Te₃, ML-Si₂Te₂, and 1QL-Sb₂Te₃ films, sequentially. More importantly, the precisely engineering of the interfacial band alignment is realized, by manipulating the substrate's p-doping effect with lateral spatial dependency, on each ML-Si₂Te₂@Sb₂Te₃/1QL-Sb₂Te₃@ML-Si₂Te₂ junction. Atomically sharp interfaces of the junctions with continuous lattices are observed by scanning tunneling microscopy. Scanning tunneling spectroscopy measurements directly reveal the tailored type-II band bending at the interface. This reported strategy opens avenues for advancing lateral epitaxy technology, facilitating practical applications of 2D in-plane heterojunctions.