Coupling Quantum Confinement and Optoelectrical Probing to Unravel Hot Carrier Behavior in InGaAs Quantum Wells

Enhancing the efficiency of photovoltaic (PV) solar cells by suppressing hot carrier thermalization channels is one approach to overcome the theoretical limits of single-junction PV devices. Nanostructures can facilitate this process by slowing the rates of hot carrier relaxation and enabling their extraction. In this study, we investigate how the size of InGaAs quantum wells (QWs) affects the optoelectrical properties of hot carriers in these nanostructures. Our results indicate the presence of hot carrier populations in QWs of sizes 4 nm, 5.5 nm, and 7.5 nm, with stronger hot carrier effects observed in the thickest QW. The electrical characteristics of the QWs are influenced by quantum confinement effects; however, due to significant contributions from the barrier, the signal associated with photogenerated hot carriers in the QWs was not clearly visible. This effect underscores the critical importance of developing suitable energy-selective contacts, as well as optimizing the quantum well size for applications involving hot carrier solar cells..