Defect induced white-light emission from Mn–doped ZnO films and its magnetic properties

Sindhu, H S and Rajendra, B V and Hebbar, Deepak N and Kulkarni, Suresh D and Babu, P D (2018) Defect induced white-light emission from Mn–doped ZnO films and its magnetic properties. Journal of Luminescence, 199 (1). pp. 423-432. ISSN 0022-2313

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Abstract

Thin films of Zn1-xMnxO (where x=0.01–0.1), a transparent dilute magnetic semiconductor were grown on a glass substrate using cost-effective chemical spray pyrolysis. All films were polycrystalline and most intense XRD peak changed from (0 0 2) at lower x values to (1 0 0) plane for higher doping level. The deposits possessed the fibrous structure up to x=0.04, a flowered structure for x=0.05–0.07, and spheroid structure for x=0.08–0.10, as revealed by SEM. The visible region, optical transmittance systematically changed from 90% to 55%, with increasing dopant concentration. The optical energy band-gap decreased at higher doping levels attributed to the sp–d exchange interactions. The photoluminescence (PL) spectroscopy revealed the presence of various defects which pronounced with increasing Mn%. As a result of multiple defect induced transitions, the PL spectra spanned the entire visible spectrum. Zn.95Mn.05O films showed CIE values with x=0.333 and y=0.322, perfectly matching to that of pure white light, with a “Colour Temperature” of 5475 K. The magnetic measurements confirm that the higher Mn-doped films displayed room-temperature ferromagnetism while less doped films showed weak ferromagnetic effects at 5 K.

Item Type: Article
Subjects: Engineering > MIT Manipal > Physics
Depositing User: MIT Library
Date Deposited: 03 Jul 2018 10:42
Last Modified: 03 Jul 2018 10:42
URI: http://eprints.manipal.edu/id/eprint/151472

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