Time-resolved THz spectroscopy of proton-bombarded InP

We investigate the recombination dynamics of photoexcited carriers in proton-bombarded InP crystals using near-infrared pump–THz-probe spectroscopy. The carrier lifetime is directly related to the proton dose and hence to the induced trap density: In weakly damaged samples we observe a saturation of the trap states for high-excitation densities. For highly damaged samples the time-dependent THz transmission can be explained by taking into account an Auger-assisted trapping process.