We observed terahertz radiation from InAs/Al0.5Ga 0.5Sb heterostructures excited by femtosecond pulses of mode-locked Ti:sapphire laser in the temperature range of 20-300 K. The radiation pseudo-reflected is monitored in time domain by a low temperature grown GaAs photoswitch. Although the waveforms are almost identical irrespective of temperatures, their maximum amplitude is strongly temperature dependent and peaks at around 100 K. Laser power dependence of the amplitude indicates that the excitation at power densities above 57 W/cm2 induce saturation presumably due to screening effect. © 2003 Elsevier B.V. All rights reserved.