Transient photoresponse in amorphous In-Ga-Zn-O thin films under stretched exponential analysis

Jiajun Luo, Alexander U. Adler, Thomas O. Mason, D. Bruce Buchholz, R. P.H. Chang, M. Grayson

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

We investigated transient photoresponse and Hall effect in amorphous In-Ga-Zn-O thin films and observed a stretched exponential response which allows characterization of the activation energy spectrum with only three fit parameters. Measurements of as-grown films and 350 K annealed films were conducted at room temperature by recording conductivity, carrier density, and mobility over day-long time scales, both under illumination and in the dark. Hall measurements verify approximately constant mobility, even as the photoinduced carrier density changes by orders of magnitude. The transient photoconductivity data fit well to a stretched exponential during both illumination and dark relaxation, but with slower response in the dark. The inverse Laplace transforms of these stretched exponentials yield the density of activation energies responsible for transient photoconductivity. An empirical equation is introduced, which determines the linewidth of the activation energy band from the stretched exponential parameter β. Dry annealing at 350 K is observed to slow the transient photoresponse.

Original languageEnglish (US)
Article number153709
JournalJournal of Applied Physics
Volume113
Issue number15
DOIs
StatePublished - Apr 1 2013

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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