Determination of Optical and Thermal Properties of Nanoparticles using Photoacoustic Technique

Abstract

Recently semiconductor nanocrystals or quantum dots (QDs) have attracted a great deal of scientific interest, because of the sensitivity of their optical and non-radiative properties to their size, shape, structure and composition. In this work, a group of samples of heterostructured semiconductor nanocrystals was prepared via a two-step method of organometallic synthesis. First, we prepared nanocrystals of CdTe which served as the core material, and then we subsequently over grew a shell of four different thicknesses of CdSe in a second step.

All prepared samples were characterized usmg HRTEM to determine their size distribution and crystal structure. The UV-Vis optical absorption and photoluminescence spectroscopy has been measured to the prepared samples. It was found that type-II quantum dots of CdTe/CdSe core/shell could be achieved with shell thickness larger than 2 ML for a core size of 34 A.