Studies on cu2sns3 and pbsexs1x Quantum dots for optoelectronic applications

Abstract

Nanotechnology allows the optoelectronics and solar cell industry to enhance to an accelerated state, despite the need for newer materials and their process for developing advances in optoelectronics devices and the solar cell. Compared with other industries, it is important to develop newer materials with cost effective, most environments friendly and less toxic features. Among these newer materials, quantum dots (QDs) is the gold dust of optoelectronics and solar cells industry which enhances the devices with highest efficiency and more stability. The unique density of states and associated carrier dynamic properties of QDs make highly interesting ultrafast optical properties. The application of QDs plays a major role in the field of optical fiber communication such as laser source, photodetectors, etc. Compatibility with photonic integration of circuits requires the operation of QDs operating at 1.31 and#956;m and optical wavelength at 1.55 and#956;m. Synthesis, characterization and fabrication of these devices are costly and highly time consuming. Hence, a theoretical model based on quantum electronic principle will be expedient in characterizing and optimizing the performance of the devices. This thesis discusses the modeling and some experimental studies of Cu2SnS3 QDs and PbSexS1-x QDs to assess the opportunity for utilization in optoelectronics and solar cells applications. The theoretical models based on Vegard s law, Brus model, Bohr principle and density of states calculation have been developed for the analysis of electronic and optical transitions of QDs. The advantage of these models over classical physical principles is that they systematically predict the energy bandgap, exciton Bohr radius, available energy states per unit energy per unit volume and wavelength of QDs by varying the mole fraction of the alloy at different design parameters. The results show a tradeoff between mole fraction and energy bandgap and size of Cu2SnS3 and PbSexS1-x material and as inversely proportional to wavelength. newline