Carrier dynamics and conductivity of SnO2 nanowires investigated by time-resolved terahertz spectroscopy

THz spectroscopy has been applied to investigate the photo-induced and intrinsic conductivity in SnO2 nanowires using the Drude-Smith model. The refractive index of the nanowires was found to decrease from 2.4 to 2.1 with increasing THz frequency and the dc mobility of the non-excited nanowires was determined to be 72 ± 10 cm2/Vs. Measurements reveal that scattering times are carrier density dependent, while a strong suppression of long transport is evident. Intensity-dependent measurements provided an estimate of the Auger coefficient found to be γ = (7.2 ± 2.0) × 10−31 cm6/s.