Understanding the transport and contact properties of metal/BN-MoS2 interfaces to realize high performance MoS2 FETs

Abstract

Understanding the nature of contact with BN buffer layer is vital to realize high performance monolayer MoS2 nanodevice. Here, effects of BN buffer layer with different sizes and defects on the transport and contact properties of metal/BN-MoS2 interfaces in six typical field effect transistors are comprehensively studied. No matter what the sizes or defects for BN buffer layer, the room-temperature electron mobilities (93.15 cm2V−1s−1) of MoS2 channel layer and Fermi level pinning (∼0.43) of metal/BN-MoS2 interfaces are not deteriorated, and all Schottky barriers at the metal/BN regions of metal/BN-MoS2 interfaces are vanished. Interestingly, Schottky barriers the BN-MoS2 regions of metal/BN-MoS2 interfaces are irrelevant to the size of BN buffer layer, but reduced and enhanced by electron-poor and rich defects, respectively; while Schottky barriers between metal/BN-MoS2 interfaces and MoS2 channel layers are enhanced by all defects, and related to the sizes of defective BN buffer layers. Consequently, just when metal/BN-MoS2 interfaces possess large size BN buffer layer, and meanwhile electron-poor defects locate at the channel region, the effective Schottky barriers are further reduced. In addition, tunnel barriers of metal/BN-MoS2 interfaces are irrelevant to the sizes of BN buffer layers, but are reduced by electron-rich defects. These works systematically elucidate the contact and transport properties of metal/BN-MoS2 interfaces and provide a promising way to design high performance monolayer FETs with lower Schottky barriers by defective BN buffer layer.