Faster photoswitching and amplified NBE emission from mg doped sol-gel derived ZnO thin films

ABSTRACT

Photoconductivity and photoluminescence of highly transparent predominantly c-axis oriented hexagonal wurtzite nanocrystalline Mg doped zinc oxide thin films are reported here. These films prepared by sol-gel spin coating are useful for switching and UV detector applications. The increase in dopant concentration tunes the optical band-gap from 3.15 to 3.41 eV. Amplified NBE emission with low defect emission is obtained in appropriately doped sample along with high suitability for switching applications since the photocurrent sharply falls to a very low value as the illumination is put off and the rise and decay pattern is reproducible for several consecutive cycles. The films have crystallite size less than 16 nm and rod-like structures of diameter 50 to 100 nm are seen to grow out of spherical granular background. Doping reduces the size of grains and rods as well as the surface roughness.

KEYWORDS:

• Mg-doped-ZnO
• optical band gap
• photoresponse
• photoconductivity
• photoswitching
• photoluminescence

Acknowledgments

Authors are thankful to DST New Delhi India for providing UV-Vis-NIR spectrometer (vide project no.SR/S2/CMP −0028/2010), and to the Department of Biotechnology, New Delhi, Government of India for providing financial assistance vide project no. BT/PR40089/NER/95/1663/2020. Thanks, are also due to Govt. of Uttar Pradesh for providing XRD facility, to DST New Delhi for providing AFM facility through PURSE grant, and to UGC New Delhi for providing Fluorescence spectrometer facility through SAP.

Disclosure statement

No potential conflict of interest was reported by the authors.