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UV-visible Absorbtion Studies of ZnSe Chalcogenide Quantum Dots
P. Yousaf Khan, Manju Singhal, J.K. Sharma, Chung Hsin Lu and Sunil Kumar

ZnSe chalcogenide quantum dots have been synthesized using chemical precipitation technique at variable pH values. In this paper, effect of pH is seen on the size of ZnSe quantum dots. It is observed that, the size of ZnSe nanoparticles vary with the variation in pH of the precursors used and the quantum dot structures are fabricated at pH of 0.5 and 1.5 only. The band gap measurements are done by using absorption coefficient of ZnSe quantum dots and nanoparticles at different pH values which is calculated by plotting absorbance and wavelength. The bandgap is further calculated by plotting (αhν)1/2 vs. hν. The particle size is calculated from brus equation which also confirms the quantum confinement effects occurring in ZnSe quantum dots. The absorption edge is used for the calculation of particle size in case of ZnSe nanoparticles. These optical studies are very useful from optoelectronic application point of view of ZnSe quantum dots and nanoparticles.

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