Temperature dependence of carrier relaxation in semiconductor doped glasses

Two-color picosecond pump-probe measurements in semiconductor nanocrystallite doped glasses reveal nonexponential decay of photoexcited carriers. The dependence of the decay on nanocrystallite size, pump intensity, temperature, and probe wavelength are examined and discussed within the framework of continuous-time random-walk models for transport of carriers among localized trap sites. This analysis suggests that carrier transport in lower dimensions is involved in the relaxation of these nano- scale systems.