Fe-implanted InGaAs terahertz emitters for 1.56μm wavelength excitation

We have measured the terahertz (THz) radiations from unimplanted and Fe-implanted ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ photoconductive switches excited by the femtosecond laser pulse of $1.56\mu \mathrm{m}$ wavelength. It has been also observed that the amplitude of the radiated wave form from these photoswitches deviates from linear behavior, and saturates with increase in the power of excitation pulse. Fe implantation to the samples leads to about 1.2 times decrease in the pulse width of radiated THz wave form and 6.5 times reduction in the carrier mobility compared to the unimplanted sample.