An Investigation on the Fabrication of Heterojunctions and Resistive Memory Devices Using Iron and Magnesium Based Quaternary Chalcogenide thin Films

Abstract

This thesis presents a detailed study of copper based quaternary chalcogenide thin films and their potential applications in renewable energy sector and neuromorphic computing. Copper based quaternary chalcogenide compounds are of great significance because of their applications in photovoltaics, photocatalysis, memory switching devices, supercapacitors and so on. These materials can be deposited using multiple methods, including thermal evaporation, spray pyrolysis and sputtering, electron beam evaporation, spin coating, chemical bath deposition etc. newlineCu2FeSnS4 (CFTS) thin films have been deposited using vacuum spray pyrolysis technique. The structural, morphological, electrical and optical properties of the films have been analysed. The films exhibited high absorption in the visible range of light and have high values of conductivity and mobility. Heterojunction devices with architecture ltFTO/AZO/CFTS/Aggt and ltFTO/AZO/CdS/CFTS/Aggt have been fabricated and the junction parameters are evaluated. Cu2MgSnS4 (CMTS) thin films have been deposited using vacuum spray pyrolysis technique. The effect of annealing temperature on the structural, morphological, electrical and optical properties of the films have been analysed. The films showed high values of absorption coefficient and have high values of conductivity and mobility. Heterojunction devices with architecture ltFTO/AZO/CMTS/Aggt and ltFTO/AZO/CdS/CMTS/Aggt have been fabricated and the junction parameters are calculated. newlineCu2FeSnS4 thin films are used as active layer in resistive memory switching devices. The influence of different top electrodes on the device properties has been investigated. Devices with architecture ltFTO/CFTS/Aggt and ltFTO/CFTS/Algt have been fabricated. The I-V characteristics of the devices are evaluated and endurance characteristics have been studied to find out the electrode with better device performance. Resistive memory switching devices were fabricated using Cu2MgSnS4 thin films as active layer. Silver and Aluminium were used as top electrodes