中国物理B ›› 2021, Vol. 30 ›› Issue (6): 68501-068501.doi: 10.1088/1674-1056/abd752

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Effect of electrical contact on performance of WSe2 field effect transistors

Yi-Di Pang(庞奕荻), En-Xiu Wu(武恩秀), Zhi-Hao Xu(徐志昊), Xiao-Dong Hu(胡晓东), Sen Wu(吴森), Lin-Yan Xu(徐临燕), and Jing Liu(刘晶)†   

  1. State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China
  • 收稿日期:2020-10-17 修回日期:2020-11-26 接受日期:2020-12-30 出版日期:2021-05-18 发布日期:2021-05-18
  • 通讯作者: Jing Liu E-mail:jingliu_1112@tju.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 52075385), the National Key R&D Program of China (2018YFA0307200), and the 111 Project (Grant No. B07014).

Effect of electrical contact on performance of WSe2 field effect transistors

Yi-Di Pang(庞奕荻), En-Xiu Wu(武恩秀), Zhi-Hao Xu(徐志昊), Xiao-Dong Hu(胡晓东), Sen Wu(吴森), Lin-Yan Xu(徐临燕), and Jing Liu(刘晶)†   

  1. State Key Laboratory of Precision Measurement Technology and Instruments, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China
  • Received:2020-10-17 Revised:2020-11-26 Accepted:2020-12-30 Online:2021-05-18 Published:2021-05-18
  • Contact: Jing Liu E-mail:jingliu_1112@tju.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 52075385), the National Key R&D Program of China (2018YFA0307200), and the 111 Project (Grant No. B07014).

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摘要： Two-dimensional (2D) transition metal dichalcogenides (TMDCs) such as tungsten diselenide (WSe2) have spead many interesting physical properties, which may become ideal candidates to develop new generation electronic and optoelectronic devices. In order to reveal essential features of 2D TMDCs, it is necessary to fabricate high-quality devices with reliable electrical contact. We systematically analyze the effect of graphene and metal contacts on performance of multi-layered WSe2 field effect transistors (FETs). The temperature-dependent transport characteristics of both devices are tested. Only graphene-contacted WSe2 FETs are observed with the metal-insulator transition phenomenon which mainly attributes to the ultra-clean contact interface and lowered contact barrier. Further characterization on contact barrier demonstrates that graphene contact enables lower contact barrier with WSe2 than metal contact, since the Fermi level of graphene can be modulated by the gate bias to match the Fermi level of the channel material. We also analyze the carrier mobility of both devices under different temperatures, revealing that graphene contact can reduce the charge scattering of the device caused by ionized impurities and phonon vibrations in low and room temperature regions, respectively. This work is expected to provide reference for fabricating 2D material devices with decent performances.

关键词: two-dimensional materials, tungsten diselenide, metal-insulator transition, Schottky barrier, contact

Abstract: Two-dimensional (2D) transition metal dichalcogenides (TMDCs) such as tungsten diselenide (WSe2) have spead many interesting physical properties, which may become ideal candidates to develop new generation electronic and optoelectronic devices. In order to reveal essential features of 2D TMDCs, it is necessary to fabricate high-quality devices with reliable electrical contact. We systematically analyze the effect of graphene and metal contacts on performance of multi-layered WSe2 field effect transistors (FETs). The temperature-dependent transport characteristics of both devices are tested. Only graphene-contacted WSe2 FETs are observed with the metal-insulator transition phenomenon which mainly attributes to the ultra-clean contact interface and lowered contact barrier. Further characterization on contact barrier demonstrates that graphene contact enables lower contact barrier with WSe2 than metal contact, since the Fermi level of graphene can be modulated by the gate bias to match the Fermi level of the channel material. We also analyze the carrier mobility of both devices under different temperatures, revealing that graphene contact can reduce the charge scattering of the device caused by ionized impurities and phonon vibrations in low and room temperature regions, respectively. This work is expected to provide reference for fabricating 2D material devices with decent performances.

Key words: two-dimensional materials, tungsten diselenide, metal-insulator transition, Schottky barrier, contact

中图分类号:  (Nanoelectronic devices)

  • 85.35.-p
85.30.Tv (Field effect devices) 81.16.-c (Methods of micro- and nanofabrication and processing)