Sunday, May 10, 2015
Abstract-Lifetime-limited, subnanosecond terahertz germanium photoconductive detectors
The recombination times of photo-excited free in heavily and highly compensated are studied by a time-resolved pump-probe experiment at a frequency of ∼3 THz. The dominant in the samples is either (n-Ge:Ga:Sb) or gallium (p-Ge:Sb:Ga) with compensating levels close to 100%. The recombination time of the free measured by our pump-probe technique varies between 30 and 300 ps. It decreases with increasing pump pulse energy and increasing compensation due to high concentrations of Coulomb recombination centers. The recombination times at low pump powers are up to ten times shorter than those previously obtained for low-compensated n-Ge:Sb and p-Ge:Ga. The photoconductive made from this material shows the response time is in the order of its recombination time.