Ultrafast carrier thermalization in InN

Carrier thermalization dynamics in heavily doped n-type InN was investigated at room temperature with a femtosecond transient transmission measurement. The dependence of hot carrier cooling time on the total electron density indicates that the plasma screening of electron-LO phonon interactions is responsible for the reduction in energy-loss rate. Under low excitation, the carriers with different excess energies can be found to cool down with a fixed thermalization time of 1.4 ps. Intensity dependent study suggests that this relatively slow carrier cooling time could be attributed to the screening effect by high-background-doping plasma rather than the hot phonon effect. (c) 2006 American Institute of Physics.