Instability of UV Photoresponse in MgZnO Thin Films and Its Improvement by MgO Capping. Issue 9 (11th March 2020)

• Record Type: Journal Article
• Authors: Das, Amit K.; Sahu, Vikas K.; Ajimsha, Rohini S.; Misra, Pankaj
• Is Part Of: Physica status solidi. Volume 217:Issue 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-11
• Subjects: MgO capping layers -- MgZnO -- stability of photoresponse -- UV photoresponse; Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.202000026
• Languages: English
• ISSNs: 1862-6300

Abstract

Abstract : Herein, it is shown that the UV photoresponse characteristics of MgZnO thin films deposited by pulsed laser deposition change rapidly with time if the films are exposed to ambient air and that the response can be stabilized significantly by depositing a thin capping layer of MgO on the surface of MgZnO thin film. The decay time of photocurrent in as‐deposited MgZnO thin films increases from 1.8 to 229 s and the value of peak responsivity increases by about three orders of magnitude as the film is exposed to air for about 10 6 s. On application of MgO capping layer, the decay time of the photocurrent marginally increases from ≈0.2 to ≈0.4 s and the value of peak responsivity increases only by one order of magnitude over the span of 10 6 s, thereafter showing tendency of saturation, implying much better stability in performance. The MgO capping layer is transparent to UV, but acts as a diffusion barrier for oxygen, stabilizing the UV photoresponse. Abstract : The UV photoresponse in MgZnO films changes with time on exposure to ambient air. The photocurrent decay time increases by two orders of magnitude and peak responsivity increases by three orders of magnitude on exposure to air for just 10 6 s. The peak responsivity and photocurrent decay time can be stabilized by application of a MgO capping layer.