A Comparative Study on the Optical Properties of Multilayer CdSe / CdTe Thin Film with Single Layer CdTe and CdSe Films

Authors M. Melvin David Kumar , Suganthi Devadason

Thin Film Laboratory, Department of Physics Karunya University, Coimbatore – 641 114 India

Е-mail mailtomelvindavid@gmail.com
Issue Volume 5, Year 2013, Number 3
Dates Received 24 January 2013; revised manuscript received 14 February 2013; published online 12 July 2013
Citation M. Melvin David Kumar, Suganthi Devadason, J. Nano- Electron. Phys. 5 No 3, 03007 (2013)
PACS Number(s) 61.05.– a, 03.65.Xp, 74.78.Fk
Keywords CdSe (8) , CdTe (12) , Multilayer (11) , Heterostructure (7) , Quantum confinement (5) .
Annotation CdTe and CdSe single layer thin films and CdSe / CdTe multilayer (ML) thin film were prepared by using physical vapour deposition method. Optical properties of CdSe / CdTe multilayer thin film shows different behavior due to type II band structure alignment. Energy band gap value of CdSe / CdTe ML thin film is shifted to higher value than that of single layer CdTe film. This is due to decrease in crystallite size to dimension smaller than the Bohr exciton radius of CdTe (14 nm). Crystallite size of the multilayer sample was calculated with the predictions of the effective mass approximation model (i.e., Brus model). It is observed that the photoluminescence peak of CdSe / CdTe ML thin film is red shifted compared to the peaks corresponding to individual CdSe and CdTe thin films. This may be due to the presence of type II quantum dot formation in the CdSe / CdTe heterostructure multilayer thin film.

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