Contribution of type II quantum dot InAlAs/AlGaAs to enhance solar cell performance

The purpose of this research deals with the investigation of optical, electrical and structural properties of III-V semiconductor materials and nanostructures with applications in the development of next generation solar... [ view full abstract ]

The purpose of this research deals with the investigation of optical, electrical and structural properties of III-V semiconductor materials and nanostructures with applications in the development of next generation solar cells. In particular, the focus is on the study of type II quantum dots (QDs) with long carrier lifetimes resulting from the spatial separation of carriers which provides additional advantage in solar cell absorber. AlInAs/AlGaAs QDs is one of the quantum structures that give rise to type-II QDs. Such QDs present a peculiar electronic structure and give the possibility to control and investigate the type-I to type-II crossover. Tailoring of the band alignment, the wave function overlaps and hence the carrier dynamics in these nanostructures is necessary for practical applications. This study presents an band-alignment tailoring of AlInAs/AlGaAs QDs structure for intermediate-band solar cell (IBSCs) application. The intermixing, caused by thermal annealing at the AlInAs/AlGaAs interface, will lead to a favorable electronic band alignment, necessary for high-efficiency solar cell devices. In this study QDs size, material composition and anneal temperature have to be optimised to give the maximum efficiency.