I am trying to figure out what information can I get with the help of PL spectra and how to analyse it? How to do the defect analysis, if I am using two different material for thin film how will that effect my PL spectra? I will be thankful to my research community and fellow researchers if I can get an answer.
Dear Pooja Punetha ,
For the theoretical background you have to study optoelectronic properties of material which concerns the optical effects on the material and how the incident photon with specific wavelength interact with the electrons in the material.
Apart from reflecting part of the incident optical radiation, part of the photons penetrating the material will be absorbed by electrons in the valence band and an electron hole pair is generated. These electron hole pairs are called excitons.
Excitons can be dissociated thermally or by an electric field to form free electrons and holes. Both excitons and electrons and holes can recombine again either radiatively or nonradiatively. Only the radiative recombination results in the photoluminescence. While the radiative recombination is intrinsic the nonradiative recombination depends on the presence of recombination centers which may be crystallographic defects of an impurity. The wavelength lambda of the radiated photons depend on the energy gap Eg of the material. Namely Eg= hc/lambda where h is the Planck constant and c is the speed of light.
From the principle point of view the generated light spectrum depends on the energy band structure of the material.
You can study the spectrum of a material by using photospectrometer.
You can yourself build such photospectrometer by optical filters, LEDs and photodetector.
For more information please follow the paper in the link:Article LED Based Spectrophotometer can compete with conventional one
Dear Pooja Punetha ,
For the theoretical background you have to study optoelectronic properties of material which concerns the optical effects on the material and how the incident photon with specific wavelength interact with the electrons in the material.
Apart from reflecting part of the incident optical radiation, part of the photons penetrating the material will be absorbed by electrons in the valence band and an electron hole pair is generated. These electron hole pairs are called excitons.
Excitons can be dissociated thermally or by an electric field to form free electrons and holes. Both excitons and electrons and holes can recombine again either radiatively or nonradiatively. Only the radiative recombination results in the photoluminescence. While the radiative recombination is intrinsic the nonradiative recombination depends on the presence of recombination centers which may be crystallographic defects of an impurity. The wavelength lambda of the radiated photons depend on the energy gap Eg of the material. Namely Eg= hc/lambda where h is the Planck constant and c is the speed of light.
From the principle point of view the generated light spectrum depends on the energy band structure of the material.
You can study the spectrum of a material by using photospectrometer.
You can yourself build such photospectrometer by optical filters, LEDs and photodetector.
For more information please follow the paper in the link:Article LED Based Spectrophotometer can compete with conventional one
Thank you so much Dr. Abdelhalim abdelnaby Zekry I am glad, you answered my question. Thank you for the reply.
Daar Pooja,
For the analysis of defects, techniques of thermoluminescence measurements are often used. However, the optical characterisation of matter by PL spectroscopy is i the focus of one of my lectures "Electrical and Optical Characterisation of Materials", which is taught by Dr. Florian Baur (also on RG) and me. Here is the link to the lecture slides. You do not need any password, just open the link:
https://www.fh-muenster.de/ciw/downloads/personal/juestel/juestel/Materialcharakterisierung_FB__englisch__.pdf
All the best,
Thomas
Thank you Dr. Thomas Jüstel , I am thankful that you answered my question. I will surely watch the lecture (ppt. attached) carefully, to get answer to my queries. Thank you again.
https://iopscience.iop.org/article/10.1088/1742-6596/995/1/012067/pdf
Article Low Temperature Photoluminescence Spectroscopy of Defect and...
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