The role of nonequilibrium LO phonons, Pauli exclusion, and intervalley pathways on the relaxation of hot carriers in InGaAs/InGaAsP multi-quantum-wells

Under continuous-wave laser excitation in a lattice-matched In0.53Ga0.47As/In0.8Ga0.2As0.44P0.56 multi-quantum-well (MQW) structure, the carrier temperature extracted from photoluminescence rises faster for 405 nm compared with 980 nm excitation, as the injected carrier density increases. Ensemble Monte Carlo simulation of the carrier dynamics in the MQW system shows that this carrier temperature rise is dominated by nonequilibrium LO phonon effects, with the Pauli exclusion having a significant effect at high carrier densities. Further, we find a significant fraction of carriers reside in the satellite L-valleys for 405 nm excitation due to strong intervalley transfer, leading to a cooler steady-state electron temperature in the central valley compared with the case when intervalley transfer is excluded from the model. Good agreement between experiment and simulation has been shown, and detailed analysis has been presented. This study expands our knowledge of the dynamics of the hot carrier population in semiconductors, which can be applied to further limit energy loss in solar cells.

Automated summary

Under continuous-wave laser excitation, the carrier temperature in a lattice-matched MQW structure exhibits a faster rise for 405 nm compared to 980 nm excitation, as the injected carrier density increases. The dominant factor for this temperature rise is nonequilibrium LO phonon effects, with the Pauli exclusion playing a significant role at high carrier densities. Additionally, the study reveals the presence of carriers in satellite L-valleys due to strong intervalley transfer during 405 nm excitation, resulting in a cooler steady-state electron temperature in the central valley. This research enhances our understanding of hot carrier dynamics in semiconductors and can be applied to reduce energy loss in solar cells.