Investigation of size dependent structural and optical properties of thin films of CdSe quantum dots

Research highlights: → CdSe q-dots have been synthesized using simple chemical synthesis route. → Thin film of CdSe quantum dots exhibited self-organized growth. → Size dependent blue shift observed in the absorption edge of CdSe nanocrystallites. → PL emission band corresponds to band edge luminescence and defect luminescence. → Organized growth led to enhancement in luminescence yield of smaller size Q-dots. -- Abstract: Cadmium selenide (CdSe) quantum dots were grown on indium tin oxide substrate using wet chemical technique for possible application as light emitting devices. The structural, morphological and luminescence properties of the as deposited thin films of CdSe Q-dot have been investigated, using X-ray diffraction, transmission electron microscopy, atomic force microscopy and optical and luminescence spectroscopy. The quantum dots have been shown to deposit in an organized array on ITO/glass substrate. The as grown Q-dots exhibited size dependent blue shift in the absorption edge. The effect of quantum confinement also manifested as a blue shift of photoluminescence emission. It is shown that the nanocrystalline CdSe exhibits intense photoluminescence as compared to the large grained polycrystalline CdSe films.