The resistivity of the undoped In0.53Ga0.47As photoconductive semiconductor switch has been measured over a temperature range of 5–300 K. The experimental temperature characteristic curve of the resistivity exhibits unimodality, and the peak resistivity is more than two orders of magnitude greater than that at 300 K. Based on the two-level model (shallow donor impurities level and deep defect level), we analyzed carrier relaxation rate due to scattering by ionized impurity and polar optical phonons. It is found that the unusually thermal characteristics is dominated by scattering of donor states by ionized impurity scattering and polar optical phonon scattering. The theoretical result is in very good agreement with the experimental results. Our results provide quantitative understanding of charge relaxation in InxGa1−xAs-based devices. Understanding of thermal properties of dark resistance can be used to optimize InxGa1−xAs-based electronic and photonic devices performance in different temperature regimes.