I have analyzed the TRPL spectrum of a ZnO thin film with the help of tri-exponential function. As a result, I have got three lifetimes. Tau 1 and Tau 2 are the exitonic lifetimes. But, I want to know the physical significance of Tau 3 which is may be due to the defect states present in the sample.
We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results
Dear Santanu, as an inorganic chemist I do not have sufficient insight into this problem to give you a qualified answer. All I can do is suggest to you a few potentially useful articles. Apparently pioneering work in this field has been published in 2006. Please have a look at this article:
Defects in virgin and N+-implanted ZnO single crystals studied by positron annihilation, Hall effect, and deep-level transient spectroscopy
Article Defects in virgin and N-implanted ZnO single crystals studie...
This paper can be accessed as public full text on the internet. If it doesn't work, you can certainly request the full text directly from one of the authors. Five authors of this paper have RG profiles.
The following article could also be of interest in this respect (no guarantee 😎):
Vacancy cluster in ZnO films grown by pulsed laser deposition
https://www.nature.com/articles/s41598-019-40029-3
This article has been published Open Access and can be freely downloaded (see attached pdf file).
I hope this helps. Good luck with your work and best wishes, Frank Edelmann
P.S. One of the other answers given to your question is a copy-and-paste plagiarism from the following RG link (Abstract):
Article Structural, Optical Constants and Photoluminescence of ZnO T...
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