PHOTODETECTORS PERFORMANCE OF NANOSTRUCTURED MATERIALS IN ANTIMONY III-V InGaAsSb/AlGaAsSb INTERBAND CASCADE STRUCTURES

The aim of the study is to increase the performance of solar conversion by integrating nanostructured materials within conventional solar cells by employing multi-energy stages (i.e., interband and intersubband) in cascade systems to overcome the absorption length barrier and achieve large photo-generated carrier values. Specifically, InGaAsSb/Al GaAsSb MQWs are investigated with narrow well widths (2-20 nm) and transition energies of the structures are calcu-lated for varied well/barrier widths and depths using numer-ical modelling. The results show that both interband and intersubband transitions are valuable for improving photo-voltaic and photodetection applications, but their mecha-nisms and applications are distinct, so understanding and controlling these transitions within semiconductor materials is essential for optimising the performance of devices in both areas of optoelectronics, including strain as an important parameter of integrity. The data suggests that a single elec-tron requires multiple photons to be transported, with the formation of a type-I broken-gap alignment between AlGa AsSb (barrier) and InGaAsSb (well). A wide range of wave-lengths, from visible to medium infrared (MIR), will greatly enhance solar spectrum absorption. The long-term goal is to combine the thermal properties of antimonies (GaSbInSb) with a low band gap and the optical properties of arsenide (GaAsAlAs) with a large band gap.