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

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...

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Bibliographic Details
Published in:Micromachines (Basel) 2023-09, Vol.14 (10), p.1860
Main Authors: Basyooni-M. Kabatas, Mohamed A., En-nadir, Redouane, Rahmani, Khalid, Eker, Yasin Ramazan
Format: Article
Language:English
Subjects:
atomic layer deposition
Bias
Carrier density
Electric potential
Electrons
Excitons
Graphene
High temperature effects
Lasers
Light
low roughness optoelectronic devices
molybdenum oxide
Ohmic dissipation
Optoelectronic devices
Photoconductivity
Photoelectric effect
Photometers
Resistance heating
sputtering deposition
Thickness
Thin films
Transistors
urbach tail energy
Voltage
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Summary: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.
ISSN:2072-666X
2072-666X
DOI:10.3390/mi14101860