Impact of the excitation wavelength on the properties of photo-generated hot carriers in InGaAs MQW

Suppersion of phonon-mediated hot carrier themalization can boost the efficiency of solar cells above the Shockley-Quesseir limit. To design hot carrier absorbers with inhibited thermalization loss, the properties of hot carriers in the system must be further investigated. Here, the impact of the excitation wavelength on hot carrier properties in an InGaAs MQW structure at various lattice temperatures and excitation intensities is studied. It is observed that the temperature of hot carriers for a given photon flux is significantly larger for a shorter excitation wavelength, however, by considering the thermalized power above the absorber band edge, the temperature of hot carriers changes with similar behavior for the various excitation wavelengths, indicating a unique thermalization coefficient for the system. Similar effect is also observed in thin GaAs absorbers. Moreover, the impacts of excitation wavelength on the quasi-Fermi level splitting and the spectral linewidth broadening of the radiation are investigated.