High Mobilities in Layered InSe Transistors with Indium-Encapsulation-Induced Surface Charge Doping

Mengjiao Li; Che-Yi Lin; Shih-Hsien Yang; Yuan-Ming Chang; Jen-Kuei Chang; Feng-Shou Yang; Chaorong Zhong; Wen-Bin Jian; Chen-Hsin Lien; Ching-Hwa Ho; Heng-Jui Liu; Rong Huang; Wenwu Li; Yen-Fu Lin; Junhao Chu

doi:10.1002/adma.201803690

High Mobilities in Layered InSe Transistors with Indium-Encapsulation-Induced Surface Charge Doping

Adv Mater. 2018 Nov;30(44):e1803690. doi: 10.1002/adma.201803690. Epub 2018 Sep 14.

Authors

Mengjiao Li¹, Che-Yi Lin², Shih-Hsien Yang³, Yuan-Ming Chang⁴, Jen-Kuei Chang⁴, Feng-Shou Yang⁴, Chaorong Zhong¹, Wen-Bin Jian², Chen-Hsin Lien³, Ching-Hwa Ho⁵, Heng-Jui Liu⁶, Rong Huang¹, Wenwu Li¹, Yen-Fu Lin⁴, Junhao Chu¹

Affiliations

¹ Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering, East China Normal University, Shanghai, 200241, China.
² Department of Electrophysics, National Chiao Tung University, Hsinchu, 300, Taiwan.
³ Department of Electrical Engineering and Institute of Electronic Engineering, National Tsing Hua University, Hsinchu, 300, Taiwan.
⁴ Department of Physics, National Chung Hsing University, Taichung, 40227, Taiwan.
⁵ Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei, 106, Taiwan.
⁶ Department of Materials Science and Engineering, National Chung Hsing University, Taichung, 40227, Taiwan.

PMID: 30589465
DOI: 10.1002/adma.201803690

Abstract

Tunability and stability in the electrical properties of 2D semiconductors pave the way for their practical applications in logic devices. A robust layered indium selenide (InSe) field-effect transistor (FET) with superior controlled stability is demonstrated by depositing an indium (In) doping layer. The optimized InSe FETs deliver an unprecedented high electron mobility up to 3700 cm² V^-1 s^-1 at room temperature, which can be retained with 60% after 1 month. Further insight into the evolution of the position of the Fermi level and the microscopic device structure with different In thicknesses demonstrates an enhanced electron-doping behavior at the In/InSe interface. Furthermore, the contact resistance is also improved through the In insertion between InSe and Au electrodes, which coincides with the analysis of the low-frequency noise. The carrier fluctuation is attributed to the dominance of the phonon scattering events, which agrees with the observation of the temperature-dependent mobility. Finally, the flexible functionalities of the logic-circuit applications, for instance, inverter and not-and (NAND)/not-or (NOR) gates, are determined with these surface-doping InSe FETs, which establish a paradigm for 2D-based materials to overcome the bottleneck in the development of electronic devices.

Keywords: 2D electronics; InSe transistors; logic circuits; low‐frequency noise; surface charge transfer doping.

Abstract

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