High-mobility three-atom-thick semiconducting films with wafer-scale homogeneity

Abstract

The large-scale growth of semiconducting thin films forms the basis of modern electronics and optoelectronics. A decrease in film thickness to the ultimate limit of the atomic, sub-nanometre length scale, a difficult limit for traditional semiconductors (such as Si and GaAs), would bring wide benefits for applications in ultrathin and flexible electronics, photovoltaics and display technology^1,2,3. For this, transition-metal dichalcogenides (TMDs), which can form stable three-atom-thick monolayers⁴, provide ideal semiconducting materials with high electrical carrier mobility^5,6,7,8,9,10, and their large-scale growth on insulating substrates would enable the batch fabrication of atomically thin high-performance transistors and photodetectors on a technologically relevant scale without film transfer. In addition, their unique electronic band structures provide novel ways of enhancing the functionalities of such devices, including the large excitonic effect¹¹, bandgap modulation¹², indirect-to-direct bandgap transition¹³, piezoelectricity¹⁴ and valleytronics¹⁵. However, the large-scale growth of monolayer TMD films with spatial...