Intriguing electronic properties of germanene/ indium selenide and antimonene/indium selenide heterostructures

The structural and electronic properties of the germanene/indium selenide (Ge/InSe), antimonene/indium selenide (Sb/InSe) heterostructures and the effects of in-plane strains on their electronic structures are investigated by performing comprehensive DFT calculations. The results show that the hybridization of the interbedded Se- and Ge- (Sb-) p orbitals can increase the binding strength between the InSe and Ge (Sb) monolayers. It is noteworthy that the band gap of germanene is opened by realizing the Ge/InSe heterostructure. In the case of the Sb/InSe heterostructure, all the stacks have direct bandgaps varying from 126.2 meV to 563.7 meV. In addition, strain has significant influence on the band structure. In the C-stacking Ge/InSe, a suitable -2% compression and 4% stretch can trigger the semiconductor-metal transition. Remarkably, an indirect-direct bandgap and semiconductor-metal transition have been observed under sufficient strain in the elastic range in the C-stacking Ge/InSe. These theoretical results could provide useful guidelines for applications of the Ge/InSe and Sb/InSe heterostructures in many fields of nanoelectronics, such as field-effect devices, optoelectronic applications, and strain sensors.