Ambipolar Light-Emitting Transistors on Chemical Vapor Deposited Monolayer MoS2

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• 作者：Evgeniy Ponomarev ; Ignacio Guti茅rrez-Lezama ; Nicolas Ubrig ; Alberto F. Morpurgo
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：15
• 期：12
• 页码：8289-8294
• 全文大小：372K
• ISSN：1530-6992

文摘

We realize and investigate ionic liquid gated field-effect transistors (FETs) on large-area MoS₂ monolayers grown by chemical vapor deposition (CVD). Under electron accumulation, the performance of these devices is comparable to that of FETs based on exfoliated flakes. FETs on CVD-grown material, however, exhibit clear ambipolar transport, which for MoS₂ monolayers had not been reported previously. We exploit this property to estimate the bandgap 螖 of monolayer MoS₂ directly from the device transfer curves and find 螖 鈮?2.4鈥?.7 eV. In the ambipolar injection regime, we observe electroluminescence due to exciton recombination in MoS₂, originating from the region close to the hole-injecting contact. Both the observed transport properties and the behavior of the electroluminescence can be consistently understood as due to the presence of defect states at an energy of 250鈥?00 meV above the top of the valence band, acting as deep traps for holes. Our results are of technological relevance, as they show that devices with useful optoelectronic functionality can be realized on large-area MoS₂ monolayers produced by controllable and scalable techniques.