Demonstration of Layered Indium Selenide Tunneling Field-effect Transistor with Ultra-thin Surface Oxidation
Yi-Hsun Chen1*, Han-Ting Liao2, Chih-Yi Cheng1, Raman Sankar3, Fang-Cheng Chou3, Chun-Wei Chen2, Wei-Hua Wang1
1Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
2Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
3Center for Condensed Matter Sciences, National Taiwan University, Taipei, Taiwan
* Presenter:Yi-Hsun Chen, email:yhchen28@gmail.com
Two-dimensional (2D) semiconductor materials have emerged as a promising candidate for next-generation semiconductors due to the thin channel thickness and the high mobility [1]. Among 2D-material-based transistors, tunneling field-effect transistors (TFETs) incorporated ultra-thin insulating barrier enables realization of low Schottky barrier height (SBH) and high subthreshold swing (SS) [2, 3]. Previous studies, however, require additional materials to create tunneling barrier. Here, we report layered Indium Selenide (InSe) TFETs with controlled oxidation of the surface layers. For the bottom interface, the InSe TFETs channel are in contact with hexagonal boron nitride to enhance field-effect mobility by reducing charged impurity scattering and charge traps. For the InSe surface, precisely controlled atomic-scale oxidation serves as a tunneling barrier to reduce SBH and improve SS. We employ Raman, photoluminescence, and X-ray photoelectron spectroscopy to characterize the oxidation of the InSe layers. We perform transport measurement of the InSe TFETs, which exhibit field-effect mobility of 482 cm2V-1s-1 at T=2 K, the SBH of 51 meV. The SS of InSe TFETs is found to be smaller than that of InSe FETs without surface oxidation.

References
[1] Bandurin, Denis A., et al. "High electron mobility, quantum Hall effect and anomalous optical response in atomically thin InSe." Nature nanotechnology 12.3 (2017): 223-227.
[2] Liang, Shiheng, et al. "Electrical transport properties of black phosphorus based field-effect transistor with Au/Co/MgO tunneling contacts." Journal of Applied Physics 122.16 (2017): 164301.
[3] Cui, Xu, et al. "Low-temperature Ohmic contact to monolayer MoS2 by van der Waals bonded Co/h-BN electrodes." Nano Letters 17.8 (2017): 4781-4786.


Keywords: two-dimensional materials, indium selenide, tunneling field-effect transistor, surface oxidation