Delivered by Ingenta to: Guest User IP : 14.139.60.97 Mon, 25 Jun 2012 06:01:18 Copyright © 2012 American Scientific Publishers All rights reserved Printed in the United States of America Nanoscience and Nanotechnology Letters Vol. 4, 405–408, 2012 Synthesis of ZnTe Nanoparticles by Microwave Irradiation Technique, and Their Characterization Mohd. Shkir 1 2 ∗ , Suveda Aarya 1 , Rajveer Singh 1 , Manju Arora 2 , G. Bhagavannarayana 2 , and T. D. Senguttuvan 2 1 Department of Physics, Atma Ram Sanatan Dharam (ARSD) College, University of Delhi, Dhaula Kuan, New Delhi 110021, India 2 National Physical Laboratory, New Delhi 110012, India The solid state syntheses of cubic Zinc Telluride nanoparticles were successesfully achieved for the first time by microwave irradiation technique within ∼25 min as per the author’s knowledge. The crystalline phase was confirmed by powder X-ray diffraction. The crystallite size was calculated and found to be ∼40 nm. Scanning electron microscope was also used to determine the size and shape of the nanoparticles, and the average particle size was found to be ∼60 nm with spherical shapes. The particle size distribution was in range of ∼50 to 70 nm. One transverse optic (TO) and two longitudinal optic (1LO and 2LO) phonon modes were observed at 167 and 205, 408 cm -1 in the FT-Raman spectrum. The optical band gap was calculated which has found to be 2.51 eV higher than the bulk ZnTe (E g = 226 eV), it reveals a clear blue shift with an energy difference 0.25 eV, this may be due to the crystallite size, exciton or charge carrier confinement. Keywords: Semiconductors, Nanostructures, Raman Spectroscopy, Electron Microscopy, Optical Property. In recent years high attention has been given to II–VI semiconducting compounds because of their potential applications in the field of optoelectronics. II–VI semi- conductor nanoparticles/nanocrystals are currently of great interest for their practical applications such as zero dimensional quantum confined materials, in optoelec- tronics and photonics. Among the II–VI semiconduc- tors, ZnTe is one of the most attractive semiconductors which is useful for various optoelectronic devices, 1–3 such as green light-emitting diodes, electro-optic field detec- tors, photo electrochemical solar cell, and high efficient powder-phosphor screens, 4 due to its optimum energy gap (2.25 eV) 5 and low affinity (3.53 eV). 6 During the last two decades, research on quantum size semiconductor par- ticles has attracted much attention due to their exciting novel properties. 7–10 Numerous reports are available in the literature on synthesis techniques as well as poten- tial applications of nano-sized semiconductor particles. 11–15 ZnTe nanostructures have been prepared by different techniques. 16–22 This work prime goal is to synthesize the titled material in nano size with a homogeneous crystallite size within a short time from Zn and Te by cost effective method. ∗ Author to whom correspondence should be addressed. Both Zn and Se elements are sensitive towards microwave coupling. Therefore, the microwave irradiation technique provides homogenous internal and volumetric heating at rapid rates 23 24 and has been used to synthesize the ZnTe nanoparticles/nanocrystals. The crystalline structure of the synthesized nanoparticles was confirmed by powder X-ray diffraction analysis. FT-Raman spectroscopic study has been done to identify the vibrational modes present in the synthesized material. The scanning electron microscope (SEM) was used to check the morphology and measure the particle size of the synthesized nanoparticles. The optical study was carried out by fluorescence spectrophotometer. The mixture of high purity (99.998%) Zn and Te pow- der (procured from Sigma Aldrich) was taken in equimolar ratio in cylindrical ceramic container with good quality ceramic balls (in appropriate ratio) kept in the vacuum chamber and then milled for 6 hours for proper mixing and aging. After proper mixing the material were put into a good quality non reactive quartz tube and then sealed at high pressure ∼10 -6 torr. The sealed quartz tube was kept in the microwave furnace of 8.8 kW and 2.8 GHz at 950  C and then the tube containing the material was bound at the both ends with platinum wire (covered) to rock continuously through a slow moving motor for proper redistribution of material without interrupting the heat for 25 minutes. After 25 minutes the reaction was stopped and Nanosci. Nanotechnol. Lett. 2012, Vol. 4, No. 4 1941-4900/2012/4/405/004 doi:10.1166/nnl.2012.1328 405