| 초록 |
Two-dimensional (2D) transition metal dichacogenides (TMDCs) have unique physical and electrical properties. There is currently interest in taking advantage of these properties for future electronic and optoelectronic applications. In this talk, I present a simple and facile route to reversible and controllable modulation of the electrical and optical properties of WS2 and MoS2 via hydrazine doping and sulfur annealing. Hydrazine treatment of transition metal disulfides improves the field-effect mobilities and photoresponsivities of the devices. These changes are fully recovered via sulfur annealing. In the second part, I demonstrate high-mobility MoS2 field-effect transistors (FETs). Achieving low contact resistance, that greatly relates to carrier mobility, is a mandatory requirement to realize high-performance devices. For this, a graphene film was inserted between MoS2 and metal electrode as an interfacial layer. In this device, a field-effect mobility of 35 cm2 V–1 s–1, on/off current ratio of 4 × 108, and photoresponsivity of 2160 A W–1 were achieved. This is attributed to efficient charge transfer to MoS2 from metal through graphene by upshifting the Fermi level of graphene and consequently lowering the Schottky barrier height at the contacts. These results may enable the fabrication of 2D electronic and optoelectronic devices with improved performance. |
