Picosecond Raman scattering studies of carrier dynamics in In _xGa_1-xAs_1-yN_y

Picosecond Raman spectroscopy has been used to study non-equilibrium electron distributions and energy loss rate in a metal-organic-chemical-vapour- deposition-grown In_xGa_1-xAs_1-yN_y (x = 0.03 and y = 0.01) epilayer grown on GaAs substrate. It is demonstrated that for the photoexcited electronhole pair density of n ≃ 10¹⁸ cm^-3 electron distributions can be described very well by Fermi-Dirac distributions with effective electron temperatures substantially higher than the lattice temperature. From the measurement of electron temperature as a function of the pulse width of the excitation laser, the energy loss rate in In_xGa_1-xAs_1-yN_y is estimated to be about 64 meV ps^-1. These experimental results are compared with those of GaAs and important implications are given.