Department Of Physics

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Author: search.filters.author.Alegaonkar, Prashant S.Subject: search.filters.subject.Spray pyrolysis

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    High-performance and ultra-sensitive ultraviolet photodetector based on surface passivated ?-Fe2O3 thin film
    (Elsevier Ltd, 2023-03-01T00:00:00) Kaawash, Nabeel M.S.; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
    Nanostructured ?-Fe2O3 is a versatile material and has attracted extensive attention due to its promising electrochemical and photoelectrochemical properties, which are widely investigated in water splitting, photoelectrochemical devices, gas sensors, and catalysis. Moreover, its band gap (Eg = 2.0 eV) allows it to absorb visible light, but due to poor charge carrier mobility, ultrafast recombination of the photo-generated carriers, and surface oxygen vacancy defects its application as a photodetector got restricted. Herein with a surface passivated ?-Fe2O3 film deposited on the glass substrate, the ultraviolet photodetector is demonstrated. The surface passivated photodetector is sensitive to ultraviolet light, showing a substantial enhancement in the photo-responsivity of 1.41 A/W, the external quantum efficiency of 515%, the photo-sensitivity of 1650%, and a reduction in response time of 0.06 ms (for 340 nm at a bias of +30 V) as compared with the device before surface passivation (0.228 A/W, 83%, 34%, and 1.6 ms), respectively. These improved properties are observed due to the suppression of surface defects via surface passivation, which increases free carrier concentration transport across the film. The surface passivated ?-Fe2O3 thin film-based photodetector with high photo-responsivity, photo-sensitivity, high speed, and ultraviolet photoresponse is promising for practical applications, and this platform opens up new avenues for the development of low-cost, and highly efficient ultraviolet photodetectors. � 2023 Elsevier B.V.
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    Simple and Productive Method to Develop Highly Sensitive and Fast Infrared Photodetector Using Spray Deposited Nanocrystalline PbS Thin Film
    (Institute of Physics, 2023-02-16T00:00:00) Thabit, Mohammed Y. H.; Kaawash, Nabeel M. S.; Begum, Sumayya; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
    This work demonstrates the development of a highly sensitive and fast infrared photodetector using a PbS thin film deposited using a simple and scalable method known as "spray pyrolysis". An aqueous precursor solution was deposited on a glass substrate at 150 �C have a cubic phase of PbS. Silver electrodes with a 1 mm gap are drawn on the film to create photo-detector devices. Low resistive contact between the silver electrode and the PbS film is revealed from the linear I-V measurements performed in the dark and under light illumination. Under the illumination of a 100-watt tungsten lamp, the photo-responsivity, sensitivity, response time, and decay time of the PbS film were measured. The Ag/PbS/Ag photodetector device has a responsivity of 70 mA/W, a sensitivity of 200 at 30 V, and the best response and decay times of 6.4 and 15.6 ms, respectively. The photodetector device produced by this simple and low-cost fabrication method has a fast response and decay time. � Published under licence by IOP Publishing Ltd.
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    Rationally designed state-of-the-art approach for enhancing the ultraviolet photon detection performance of ZnO thin film
    (Elsevier B.V., 2022-10-07T00:00:00) Kaawash, Nabeel M.S.; Halge, Devidas I.; Narwade, Vijaykiran N.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
    Here, we demonstrate a simple and effective state-of-the-art (surface passivation) approach for enhancing the UV photo detection performance of ZnO thin films synthesized via spray pyrolysis. The surface passivated Ag/ZnO/Ag device (using polyvinyl alcohol layer) has low dark current of 1.1 nA as compared with the device without surface passivation (0.04 ?A). The significant decay in the dark current after surface passivation is due the reduction in the density of surface oxygen vacancies confirmed by PL measurements. The UV photon detection capability of the surface passivated ZnO thin film exhibits a significantly high photo response (3675), high photosensitivity (3.6 � 105), photo-responsivity (0.6 A/W) and fast response time (0.6 ms) under UV light (340 nm, 140 ?W/cm2). This straightforward approach superimposes surface defects, making the ZnO thin film more suitable for a wide range of electronic device applications while preserving the material's intrinsic properties. � 2022 Elsevier B.V.
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    Highly stable and sensitive photon detection performance of ZnO thin film for ultraviolet light
    (Elsevier B.V., 2022-04-14T00:00:00) Kaawash, Nabeel M.S.; Kejriwal, Nubbh; Halge, Devidas I.; Narwade, Vijaykiran N.; Rana, Abhimanyu S.; Dadge, Jagdish W.; Jejurikar, Suhas M.; Alegaonkar, Prashant S.; Bogle, Kashinath A.
    The photo detection characteristics of spray pyrolysis deposited ZnO thin film on glass substrate at 250 OC was demonstrated for fabrication of highly stable visible-blind UV photodetector. This photodetector exhibits lower dark current < 0.04 ?A, higher UV photosensitivity ?4750, responsivity of 0.14 A/W and detectivity of 1.24 � 1012 Jones at an average intensity of 140 ?W/cm2 of 340 nm. This Ag/ZnO/Ag device show excellent photo response (rise and decay) time of ?4 and 6 ms with external quantum efficiency of 51%. The observed photocurrent in the device is associated with adsorption and light-induced desorption of oxygen from the defect sites on the film surfaces. The adsorbed oxygen removes the electron trap centers and increasing the free carrier density in ZnO. � 2022 Elsevier B.V.