Dynamics of local photoconductivity in GaAs and InP investigated by a terahertz scanning near-field optical microscope
Phys. Rev. B 112, 045407 – Published 8 July, 2025
DOI: https://doi.org/10.1103/x8m8-zgmw
Abstract
Terahertz scanning near-field optical microscope (THz-SNOM) is employed to measure ultrafast evolution of terahertz conductivity spectra after photoexcitation of GaAs and InP wafers using ultrashort laser pulses. Unlike in GaAs, the terahertz photoconductivity decay in InP is controlled mainly by the diffusion of electrons away from the photoexcited area, and by the drift due to band bending at the surface of the semiconductor. We propose and discuss several general strategies of the analysis of signals measured using THz-SNOM, and we estimate the accuracy of the obtained near-field photoconductivity spectra.
