Ultrafast hot electron relaxation time anomaly in InN epitaxial films

Ultrafast carrier dynamics in InN epitaxial films was investigated by using femtosecond time-resolved pump-probe reflectivity measurements with a photon energy of 1.58eV. The hot electron relaxation time decreased with increasing electron density (n), measuring at n−0.5. The result was contradictory to what was expected from the hot phonon effect and the screening effect. The authors attributed this result to the important role played by electron-electron scattering in hot electron relaxation.