SPATIAL AND MOMENTUM DIFFUSION OF ENERGETIC HOLES IN InAs BY TWO COLOR PUMP-PROBE METHOD

Abstract

Time-resolved electronic Raman scattering of a direct-gap semiconductor, InAs was measured by pump-probe method. We used fundamental pulses and second harmonic pulses of mode-locked Ti:S laser as excitation sources, and fundamental pulses as the probe beam. The time-resolved Raman intensities corresponding to the transition from heavy hole band to light hole band showed different features depending on the excitation energy. In case of the fundamental beam excitation, Raman intensity decreased monotonously. On the contrary, Raman intensity under the second harmonic excitation showed a maximum at a few picosecond after excitation. From the analysis, the temperature of photo-excited hole changed from 5300K to 1300K in 2psec and from 1300K to RT within 4 psec under the second harmonics excitation. It has been shown that the time-resolved Raman scattering measurement is a useful tool to investigate dynamics of the energetic carriers.