Development and Characterization of Sub-Monolayer Quantum Dot (QD) IBSCs
Student: Najla Alnami
Degree: Ph.D., December 2019
Major Professor: Dr. Gregory Salamo
Nanoscience & Engineering
- Experimental efforts towards fabricating high efficiency and low cost intermediate band solar cells (IBSCs) have not met the predictions of theoretical efficiency of 63%.
- A novel design of intermediate band solar cells is needed for increasing the solar cell conversion efficiency by increasing the solar cell photocurrent while preventing the reduction of open circuit voltage.
- Developing and optimizing IBSCs based on sub-monolayer QDs.
- Investigating the behavior of the solar cell when the island size is varied, when the cells are doped at different doping concentrations, and when the number of sub-monolayer quantum dot (QD) stack are varied.
- Growing sub-monolayer QDs and optimizing the growth using MBE.
- Incorporate sub-monolayer QDs in IBSC structures.
- Fabricating the proposed IBSC structures using standard optical photolithography, wet etching, and metallization.
- Study the structural, optical, and electrical characteristics of the structure using: Atomic Force Microscopy, Transmission Electron Microscopy, Solar Power Conversion Efficiency measurement, External Quantum Efficiency measurement, PL measurement, and Absorption Spectroscopy.
- Growing a reference sample without sub-monolayer QDs.
- Optimizing the fabrication process of the grown IBSCs.
- The designed sub-monolayer
- QD IBSC structure
The rapid increase in intermediate band solar cell efficiency is a promising sign of the possibility of developing a commercially practical solar cell system. The IBSC in this research is designed to overcome the current IBSC limitations.
- Developing and optimizing the growth of sub-monolayer QDs.
- Investigating the behavior of the intermediate band when the sub-monolayer QD size is varied, the QDs are doped at different doping concentrations, the number of sub-monolayer QDs stack are varied.
- Studying the structural quality growth, electrical, and optical behavior of the proposed structure.