Defect and strain modulated highly efficient ZnO UV detector: Temperature and low-pressure dependent studies

Khan, MA and Singha, MK and Nanda, KK and Krupanidhi, SB (2020) Defect and strain modulated highly efficient ZnO UV detector: Temperature and low-pressure dependent studies. In: Applied Surface Science, 505 .

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Abstract

ZnO, a wide bandgap (~3.3 eV) material, can be used for ultraviolet photodetection. We have deposited ZnO thin-films on glass substrates by an automated ultrasonic spray pyrolysis system. X-ray diffraction (XRD), Raman spectroscopy suggest hexagonal wurtzite phase of prepared film and scanning electron microscope reveals its microflower like structure. The Photodetector devices have been fabricated in metal–semiconductor-metal (M−S−M) configuration. A highest responsivity of 24.38 A W−1 has been achieved at an applied bias of 5 V with the corresponding external quantum efficiency (EQE) value of 8283% for 365 nm UV irradiation. On/Off ratio of the device is ~ 454 even for a low UV intensity (1.66 mW cm−2) and the corresponding detectivity of the UV photodetector device is ~ 4.6 × 1012 cm Hz1/2 W−1. The observed high value of responsivity has been assigned to a large amount of oxygen vacancy in ZnO microflowers. Oscillation in photocurrent has been observed at low air pressure and has been assigned to a competitive dynamic process of absorption and desorption oxygen on the ZnO surface. Temperature-dependent optoelectrical properties have been analyzed based on trapping-detrapping of charge carriers in defect states and their interactions with lattice phonons

Item Type:	Journal Article
Publication:	Applied Surface Science
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to the Elsevier B.V.
Keywords:	II-VI semiconductors; Irradiation; Oxygen; Oxygen vacancies; Phonons; Photodetectors; Photons; Scanning electron microscopy; Semiconductor devices; Spray pyrolysis; Substrates; Thermal effects; Zinc oxide; Zinc sulfide, Absorption and desorptions; Competitive dynamics; External quantum efficiency; Optoelectrical properties; Semiconductor metals; Temperature dependent; Trap state; Ultrasonic spray pyrolysis, Wide band gap semiconductors
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	02 Feb 2023 05:19
Last Modified:	02 Feb 2023 05:19
URI:	https://eprints.iisc.ac.in/id/eprint/79709

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