Abstract
The measurement of THz radiation from unbiased, as-implanted and post-annealed GaAs:As + samples, is discussed. The effect of thermal annealing time on depletion field, effective carrier mobility, as well as the peak THz radiating frequency of unbiased GaAs:As + are investigated. Through analysis of the lineshapes, the current surge and optical rectification effects both contribute to the observed THz signals while the former is dominant radiation mechanism. After thermal annealing, the THz signal increases with annealing time while the peak shifts to the blue. The effective carrier mobilities of As-implanted, rapid thermal annealing, and furnace-annealed GaAs:As + materials were determined by using THz radiation as a diagnostic tool.