Investigation of deep energy levels in aluminum indium gallium phosphide based space solar cells for optimization of efficiency

InGaP based multi-junction (tandem) III-V photovoltaic cells proved to be the most efficient solar cells for space applications. However, they are not suitable for the air-mass zero solar spectrum due to a compromise in the open circuit voltage of these solar cells. Replacement of the top window of the triple junction InGaP based tandem cell with AlInGaP is anticipated to produce super high-efficiency solar cells. Higher band gap AlInGaP will also absorb additional portions of the solar spectrum when compared to lower band gap InGaP. Unfortunately, such efficiencies are not realized in practice.; Experiments were conducted to study radiation-induced defects in p-AlInGaP irradiated samples using capacitance transient methods. Deep level defects present in as-grown p-AlInGaP have not been studied to date. The objective of this research is to delve into the deep level defects of as-grown p-AlInGaP by using deep-level transient spectroscope (DLTS) and determine the cause of hindrance for attaining the predicted efficiency. Three samples of as-grown p-AlInGaP comprised of different compositions of aluminum were studied in this research. In view of in-depth analysis, it has been concluded that the deep level defects induced by aluminum play an important role in governing the efficiency of AlInGaP solar cells.