Positive and Negative Photoconductivity in Ir Nanofilm-Coated MoO3 Bias-Switching Photodetector

Journal article (2023)

Authors

Mohamed A. Basyooni-M.Kabatas Dynamics of Micro and Nano Systems - Mechanical, Maritime and Materials Engineering , Selçuk University
Redouane En-nadir University Sidi Mohammed Ben Abdellah
Khalid Rahmani Mohammed V University
Yasin Ramazan Eker Necmettin Erbakan University
Research Group
Dynamics of Micro and Nano Systems (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2023 Mohamed A. Basyooni, Redouane En-nadir, Khalid Rahmani, Yasin Ramazan Eker
DOI: https://doi.org/10.3390/mi14101860
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Published Date

2023

Language

English

Faculty

Mechanical, Maritime and Materials Engineering

Department

Precision and Microsystems Engineering

Research Group

Dynamics of Micro and Nano Systems

Abstract

In this study, we delved into the influence of Ir nanofilm coating thickness on the optical and optoelectronic behavior of ultrathin MoO3 wafer-scale devices. Notably, the 4 nm Ir coating showed a negative Hall voltage and high carrier concentration of 1.524 × 1019 cm−3 with 0.19 nm roughness. Using the Kubelka–Munk model, we found that the bandgap decreased with increasing Ir thickness, consistent with Urbach tail energy suggesting a lower level of disorder. Regarding transient photocurrent behavior, all samples exhibited high stability under both dark and UV conditions. We also observed a positive photoconductivity at bias voltages of >0.5 V, while at 0 V bias voltage, the samples displayed a negative photoconductivity behavior. This unique aspect allowed us to explore self-powered negative photodetectors, showcasing fast response and recovery times of 0.36/0.42 s at 0 V. The intriguing negative photoresponse that we observed is linked to hole self-trapping/charge exciton and Joule heating effects.