Hot carrier relaxation has been studied in GaN using femtosecond time-resol
ved optical transmission and reflection. A non-thermal electron distributio
n with a pronounced "cut-off" at E-LO is observed for up to similar to 3 ps
after photoexcitation. Monte Carlo simulations show that this behaviour is
due to a remarkably strong electron-LO phonon interaction. Excitonic effec
ts are also pronounced and strongly influence the dynamics. (C) 1999 Publis
hed by Elsevier Science B.V. All rights reserved.