Group-IV 2D materials beyond graphene on nonmetal substrates: challenges, recent progress, and future perspectives

The family of two-dimensional materials has been expanding rapidly over the last few years. Within it, a special place is occupied by silicene, germanene, and stanene due to their inherent compatibility with the existing semiconductor technology (notably for the case of silicene and germanene). Although obtaining them is not trivial due to the lack of layered bulk counterparts from which they could be mechanically exfoliated, they have been recently synthesized on a number of metallic substrates. The remarkable interaction between metals and these puckered materials, however, strongly modifies their intrinsic electronic properties, and also jeopardizes their integration into functional devices. In this context, first experimental efforts are now being devoted to the synthesis of silicene, germanene, and stanene on nonmetal substrates. Here, we review these pioneering works, present the ongoing debate, analyze, and discuss the major technical challenges and finally suggest possible novel solutions worth exploring.