Fermi-Level Pinning Mechanism in MoS<sub>2</sub> Field-Effect Transistors Developed by Thermionic Emission Theory

oleh: Yu Zhang, Xiong Chen, Hao Zhang, Xicheng Wei, Xiangfeng Guan, Yonghua Wu, Shaozu Hu, Jiale Zheng, Guidong Wang, Jiawen Qiu, Jun Wang

Format: Article
Diterbitkan: MDPI AG 2020-04-01

Deskripsi

Molybdenum disulfide (MoS<sub>2</sub>) field-effect transistors (FETs) with four different metallic electrodes (Au,Ag,Al,Cu) of drain-source were fabricated by mechanical exfoliation and vacuum evaporation methods. The mobilities of the devices were (Au) 21.01, (Ag) 23.15, (Al) 5.35 and (Cu) 40.52 cm<sup>2</sup>/Vs, respectively. Unpredictably, the on-state currents of four devices were of the same order of magnitude with no obvious difference. For clarifying this phenomenon, we calculated the Schottky barrier height (SBH) of the four metal–semiconductor contacts by thermionic emission theory and confirmed the existence of Fermi-level pinning (FLP). We suppose the FLP may be caused by surface states of the semiconductor produced from crystal defects.