Study the Mechanisms of Enhanced Phonon Bottleneck Effect for the Absorber of Hot Carrier Solar Cell in III-V Multiple Quantum Wells

Abstract

The most vital key to realize hot carrier solar cell is reducing carrier relaxation time to nanoseconds by phonon bottleneck effect often observed in nanostructure. However, the mechanisms underlying this are still not well understood. In this paper, we systematically investigated the mechanisms of phonon interfacial mismatch and carrier quantum confinement over phonon bottleneck effect in InN/InxGa(1-x)N multiple quantum wells (MQWs). Highly promising hot carrier lifetimes due to enhanced phonon bottleneck effect were observed in these MQWs, where the longest hot carrier lifetime is 3.2±0.12 ns. It was found the quantum confinement of carriers could play more important role in the reduction of carrier cooling rate, while the optical phonon confinement is more likely to dominate the initial carrier temperature. This study clarifies two of the most important mechanisms of phonon bottleneck effect and directs a promising application of III-V MQWs on the absorber of hot carrier solar cell.