Issue 36, 2021

Photogating-driven enhanced responsivity in a few-layered ReSe2 phototransistor

Abstract

A wide variety of two-dimensional (2D) metal dichalcogenide compounds have recently attracted much research interest due to their very high photoresponsivities (R) making them excellent candidates for optoelectronic applications. High R in 2D photoconductors is associated with trap state dynamics leading to a photogating effect, which is often manifested by a fractional power dependence (γ) of the photocurrent (Iph) at an effective illumination intensity (Peff). Here we present photoconductivity studies as a function of gate voltages, over a wide temperature range (20 K to 300 K) of field-effect transistors fabricated using thin layers of mechanically exfoliated Rhenium Diselenide (ReSe2). We obtain very high responsivities R ∼ 16500 A/W and external quantum efficiency (EQE) ∼ 3.2 × 106% (at 140 K, Vg = 60 V and Peff = 0.2 nW). A strong correlation between R and γ was established by investigating the dependence of these two quantities at various gate voltages and over a wide range of temperatures. Such correlations indicate the importance of trap state mediated photogating and its role in promoting high photo-responsivities in these materials. We believe such correlations can offer valuable insights for the design and development of high-performance photoactive devices using 2D materials.

Graphical abstract: Photogating-driven enhanced responsivity in a few-layered ReSe2 phototransistor

Supplementary files

Article information

Article type
Paper
Submitted
29 Apr 2021
Accepted
12 Jul 2021
First published
12 Jul 2021

J. Mater. Chem. C, 2021,9, 12168-12176

Author version available

Photogating-driven enhanced responsivity in a few-layered ReSe2 phototransistor

P. D. Patil, M. Wasala, R. Alkhaldi, L. Weber, K. K. Kovi, B. Chakrabarti, J. A. Nash, D. Rhodes, D. Rosenmann, R. Divan, A. V. Sumant, L. Balicas, N. R. Pradhan and S. Talapatra, J. Mater. Chem. C, 2021, 9, 12168 DOI: 10.1039/D1TC01973B

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