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Y2.8.1

Synthesis of Mercury Cadmium Telluride nanoparticles by Solvothermal method RangaRao Arnepalli and Viresh Dutta Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi-110016, India

ABSTRACT Mercury Cadmium Telluride (MCT) nanoparticles were synthesized by Solvothermal method for the first time. Mercury, Cadmium and Tellurium in compound/elemental form were added to Ethylenediamine (solvent) in the Teflon-Stainless-Steel autoclave along with a reducing agent. Different compositions of MCT were synthesized by varying the proportions of Hg and Cd to obtain Hg1-xCdxTe with x varying from 1 to 0. X-ray diffraction patterns revealed the formation of MCT nanoparticles with predominant cubic (111) phase. TEM studies revealed that the average particle size ranged from 10 to15 nm for different compositions. INTRODUCTION Mercury Cadmium Telluride (Hg1-xCdxTe (MCT)) ranks as one of the most important semiconductor materials. This semiconductor alloy system (HgTe + CdTe) has an excellent property of tunable band gap in the range of –0.3eV for semimetallic HgTe to 1.65 eV for semiconducting CdTe [1]. Because of its uniquely suitable physical, thermal and electrical properties, it finds widespread applications in the areas like thermal imaging, space surveillance, and other commercial, medical and military applications [2, 3]. MCT is particularly useful for long-wavelength IR detector technologies. In Nanocrystalline form HgTe (quantum dots and quantum wells) is widely used in telecommunication low loss optical fiber window and infrared optical amplifiers [4]. Due to the tunable bandgap of MCT, nanocrystalline MCT may be used in hybrid photovoltaics [5] by sensitizing conjugated polymers with infrared-active nanocrystals quantum dots. Nanoparticles of compound semiconductors (CdX, where X= S, Se and Te and HgTe) show interesting physical and chemical properties [6-8] and are also useful for preparing nanocrystalline thin films. Chemical methods for making these materials have been reported in the literature [9, 10]. Wet chemical synthesis CdHg(X)Te and core shell structure of CdTe and HgTe nanocrystals and colloidal synthesis of HgTe nanocrystals with strong room temperature infrared luminescence been reported [11, 12]. But in all these methods the preparation of the Nanocrystalline materials involves many complex steps and other post treatment processes. Solvothermal method has also been widely used for the synthesis of Nanocrystalline Oxide, Chalcogenide, binary and ternary semiconductors [13, 14]. But preparation of MCT nanoparticles using Solvothermal method has not been reported yet. We have established the procedure for doing this in our laboratory to utilize the simplicity of this method and also the post treatment process. In this paper the synthesis and characterization of MCT nanoparticles prepared by Solvothermal method is reported.

Y2.8.2

EXPERIMENTAL DETAILS Solvothermal method involves the physio-chemical reaction of the constituent elements under high pressure and temperature. Mercury