Studies on the synthesis and characterization of Zn1-xCd xS and Zn1-xCdxS:Mn2+ semiconductor quantum dots

Abstract

Quantum dots (3-4 nm) of Zn1-xCdxS (both free of Mn2+ and with Mn2+ incorporated) were synthesized through a novel solvothermal-microwave irradiation technique. Detailed structural analysis of the Zn1-xCdxS and Zn1-xCd xS:Mn2+ (x = 0, 0.25, 0.5, 0.75 and 1) materials was carried out using powder X-ray diffraction technique. For all the compositions, the crystallite size was controlled to less than 1.5 nm. The optical energy gap for Zn1-xCdxS was found to vary from 3.878 to 2.519 eV and for Zn1-xCd1-xS:Mn2+ it varies from 3.830 to 2.442 eV when x is increased from 0 to 1. Overall, the optical energy gap could be tuned from a minimum of 2.442 eV to a maximum of 3.878 eV. DC conductivity analysis (from 40C to 150°C) and electrical energy gap analysis for all the compositions were also performed. The dc conductivity for Zn 1-xCd1-xS solid solutions varies from 0.3840 × 10-10 to 8.7782 × 10-10 mho/m at 150°C and for Zn1-xCd1-xS:Mn2+ it varies from 0.5751 × 10-10 to 9.8078 × 10-10 mho /m at 150°C (for x = 0 to x = 1). The method of synthesis and the results observed in this investigation may assist in the fabrication of optical devices when the required operational performance falls under the range observed in the study. © 2010 2011 Taylor & Francis.