2D Lateral Heterojunction Arrays with Tailored Interface Band Bending.

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 Si 2 Te 2 grown on Sb 2 Te 3 (ML-Si 2 Te 2 @Sb 2 Te 3 ) and one-quintuple-layer Sb 2 Te 3 grown on monolayer Si 2 Te 2 (1QL-Sb 2 Te 3 @ML-Si 2 Te 2 ) on a p-doped Sb 2 Te 3 substrate. The site-specific formation of numerous periodically arranged 2D ML-Si 2 Te 2 @Sb 2 Te 3 /1QL-Sb 2 Te 3 @ML-Si 2 Te 2 lateral heterojunctions is realized solely through three epitaxial growth steps of thick-Sb 2 Te 3 , ML-Si 2 Te 2 , and 1QL-Sb 2 Te 3 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-Si 2 Te 2 @Sb 2 Te 3 /1QL-Sb 2 Te 3 @ML-Si 2 Te 2 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.