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Raman and Photoluminescence Study of Low-temperature Synthesized–Weakly Confined Nanocrystals of ZnO
Rajni Seth, K L Gosain, Neena Jaggi, Sanjay Panwar and Sunil Kumar

This paper reports the synthesis of nanocrystalline ZnO powder by a wet chemical method which was further freeze dried at a low temperature (-40°C). The samples were characterized by XRD, photoluminescence and Raman spectroscopy. Powder X-Ray diffraction revealed the pure wurtzite structure. Lattice parameters and position of crystalline planes were in good agreement with JCPDF data card No-75-1533. Lattice parameters are found to increase as compared to bulk, showing lattice expansion. Crystallite size calculated using Scherrer formula was of the order of 11nm. Photoluminescence spectrum of the ZnO powder showed a strong UV emission peak at 393 nm and a broad weak band in visible region centered at 563 nm indicating high structural and optical quality. Raman spectroscopy shows a shift in optical modes of as prepared nanocrystals.

Keywords: Wet chemical synthesis, XRD, PL-study, Kroger-Vink notations, Raman spectroscopy

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