| Enhancing UV photoresponse in zinc oxide derived from zeolitic imidazolate framework-8 through argon annealing: a study on charge trap mitigation and photocurrent dynamics |
| Jaewon Lee, Byoung-Nam Park |
| Department of Materials Science and Engineering, Hongik University, 72-1, Sangsu-Dong, Mapo-Gu, Seoul, 04066, Korea |
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Received: May 30, 2024; Revised: August 15, 2024 Accepted: August 31, 2024. Published online: September 18, 2024. |
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| ABSTRACT |
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This study examines the UV photoresponse of zinc oxide (ZnO) derived from zeolitic imidazolate framework-8 (ZIF-8), utilizing field-effect transistors (FETs) to explore the influence of charge traps on photoresponse behaviors. Initial synthesis involved thermal treatment in air to transform ZIF-8 into ZnO. Subsequent treatment in an argon atmosphere significantly enhanced the UV photoresponse, attributed to a decrease in the density of electronic trap states often linked to structural defects or impurities within the ZnO. These traps typically capture and immobilize charge carriers, reducing the material's conductivity and responsiveness to UV light. The enhanced photoresponse was evidenced by a quicker rise and shorter decay in the photocurrent time constants upon UV activation and deactivation, respectively, and the activation of a gate electric field-modulated current in the FET structure. This current modulation indicates improved charge carrier flow and enhanced control over device conductivity. The argon treatment is hypothesized to facilitate defect healing and lattice restructuring in the ZnO, expelling or passivating trap states and providing a stable environment that prevents the re-incorporation of impurities or the formation of new defects. This study demonstrates the potential of post-synthesis treatments in enhancing the photoelectrical properties of ZnO, promising advancements in the development of high-performance optoelectronic devices. |
| Key words:
ZIF-8 · ZnO · Photoresponse · Trap |
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