Study of Optical and Structural Properties of CdTe Quantum Dots Capped with ۳MPA Using Hydrothermal Method

Quantum dots (QDs) can be defined as nanoparticles (NPs) in which the movement of charge carriers is restricted in all directions. CdTe QDs are one of the most important semiconducting crystals among other various types where it has a direct energy gap of about ۱.۵۳ eV. The aim of this study is to exaine the optical and structural properties of the ۳MPA capped CdTe QDs. The preparation method was based on the work of Ncapayi et al. for preparing ۳MPA CdTe QDs, and hen, the same way was treated as by Ahmed et al. via hydrothermal method by using an autoclave at the same temperature but at a different reaction time. The direct optical energy gap of CdTe QDs is between ۲.۲۹ eV and ۲.۵۰ eV. The FTIR results confirmed the covalent bonding between the ۳ MPA ligands and the QDs surface. The XRD results revealed that the synthesized QDs have two crystal structures, wurtzite and cubic zinc blend. FESEM results confirmed that the NPs have a spherical shape with an average diameter of nearly ۳۳.۸۵ nm. TEM analysis confirmed the particle's near sphericity, with an average diameter of around ۴۹.۳۳ nm. The sudden increase in temperature led to increase the particle size. It was found that ligand addition, maintaining the solution's acidity, and autoclaving the material enhanced quantum confinement.

Keywords:

Refluxing method , Quantum dots , Aqueous method , Quantum Confinement