Silicene field-effect transistors operating at room temperature

Abstract

Free-standing silicene, a silicon analogue of graphene, has a buckled honeycomb lattice¹ and, because of its Dirac bandstructure^2,3 combined with its sensitive surface, offers the potential for a widely tunable two-dimensional monolayer, where external fields and interface interactions can be exploited to influence fundamental properties such as bandgap⁴ and band character⁵ for future nanoelectronic devices^6,7. The quantum spin Hall effect³, chiral superconductivity⁸, giant magnetoresistance⁹ and various exotic field-dependent states⁷ have been predicted in monolayer silicene. Despite recent progress regarding the epitaxial synthesis of silicene^8,9,10 and investigation of its electronic properties^11,13,14,15, to date there has been no report of experimental silicene devices because of its air stability issue¹⁶. Here, we report a silicene field-effect transistor, corroborating theoretical expectations regarding its ambipolar Dirac charge transport¹⁷, with a measured room-temperature mobility of ∼ 100 cm² V^–1 s^–1 attributed to acoustic phonon-limited transport¹⁸ and grain boundary scattering. These results are enabled by a growth–transfer–fabrication process that we have devised—silicene encapsulated delamination with native electrodes. This approach addresses a major challenge for material preservation of silicene during transfer and device fabrication and is applicable to other air-sensitive two-dimensional materials such as germanene^2,3,4 and phosphorene^19,20. Silicene's allotropic affinity with bulk silicon and its low-temperature synthesis compared with graphene or alternative two-dimensional semiconductors suggest a more direct integration with ubiquitous semiconductor technology.