Optical and Mechanical Characterization of InAs/GaAs Quantum Dot Solar Cells

State of the art triple junction solar cells have achieved in excess of 43% efficiency. In order to extend this beyond a multijunction-only design, novel approaches to photon conversion must be sought and realized. Two novel mechanisms, bandgap engineering and absorption from an intermediate state within a semiconductor bandgap show promise in this regard. A single promising approach to both of these novel mechanisms is to exploit the unique properties of nanostructured materials to extend the absorption spectrum for the ultimate improvement of solar energy conversion efficiency. In this work, it is proposed to utilize InAs quantum dot (QD) nanostructures embedded in a GaAs p-i-n solar cell device to investigate the effects of these unique properties. Theoretical and experimental approaches will be used in tandem to explore these types of devices with special attention given to mechanical issues and optical processes inherent in this type of device. In this work, typical optical, mechanical and photovoltaic experiments for these devices will be demonstrated. The techniques and analysis used here can lead to the advancement of the use nanostructures in solar cells as well as many other types of optoelectronic devices. As a result, an improved method of strain balancing (SB) three-dimensional layers is developed and implemented in QD solar cells. Along with this improved technique, a reduced InAs coverage value was found to ultimately improve the device absolute power conversion efficiency by 0.5%