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 InGaAs/InGaAsP 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.

Impact of Electron-Phonon Scattering on Optical Properties of CHNHPbI Hybrid Perovskite Material.

We numerically investigate the impact of electron-phonon scattering on the optical properties of a perovskite material (CHNHPbI). Using nonequilibrium Green function formalism, we calculate the local density of states for several values of the electron-phonon scattering strength. We report an Urbach-like penetration of the density of states in the band gap due to scattering.

Quantitative optical assessment of photonic and electronic properties in halide perovskite.

The development of high efficiency solar cells relies on the management of electronic and optical properties that need to be accurately measured. As the conversion efficiencies increase, there is a concomitant electronic and photonic contribution that affects the overall performances. Here we show an optical method to quantify several transport properties of semiconducting materials and the use of multidimensional imaging techniques allows decoupling and quantifying the electronic and photonic contributions.