Pump wavelength dependence of hot electron temperature in GaAs

We have measured the variation of the temperature of the photoexcited hot electrons in GaAs as the pump photon energy is varies from 1.54 to 2.83 eV using various dyes in N₂ laser pumped dye laser. We find that the photon flux required to obtain a given temperature (45°K) increases by a factor of 15 as the photon energy decreases from 2.83 to 1.54 eV. The results are in agreement with a simple theory, and allow us to draw interesting conclusions about energy relaxation processes in semiconductors.