Tuning the electronic properties and band alignment of GeSe/phosphorene lateral heterostructure

Lateral heterostructures provide new opportunities for tailoring the electronic properties of next-generation nanodevices. Hereon, the electronic properties and band alignment, as well as the width and strain effect of lateral heterostructures composed of germanium selenide (GeSe) and black phosphorus (BP) monolayer are systematically explored by first-principles calculations combined with nonequilibrium Green's function (NEGF) theory. The results demonstrate that GeSe/BP lateral heterostructure is a direct band gap semiconductor with type-II band alignment, in which electrons and holes are completely separated in BP and GeSe domain, respectively. The spontaneous separation of carriers is beneficial for their transport and has potential applications in unipolar electronic device. The band gaps gradually decrease with the increasing supercell width and inlayer tensile strain, and have an indirect-to-direct transition. In addition, band alignment calculations reveal that type-II to quasi type-I transition is observed through changing heterostructure width, while electron-hole pairs remain spontaneous separation with type-II band alignment under small tensile strain. The present results provide vital guidance for the investigation and modulation of electronic properties based on GeSe/BP lateral heterostructure. Furthermore, this work may further attract investigation enthusiasms on the related research based on lateral heterostructures composed by other two-dimensional materials beyond GeSe and BP.