Experimental Evidence for the Effect of Acoustic Plasmons on Carrier Relaxation in Bulk Semiconductors

Abstract

We demonstrate experimentally the role of pre--existing populations on the relaxation of nonequilibrium carriers in bulk semiconductors: A substantial acceleration is observed for cold pre--excited carriers and a slowing down for hot equilibrium carriers. Furthermore, experiments in doped samples demonstrate that holes are predominantly responsible for the acceleration of the thermalization. The experimentally observed acceleration (slowing down) is readily explained theoretically by favorable (unfavorable) conditions for the excitation of weakly damped acoustic plasmons. Typeset using REVT E X The relaxation of nonequilibrium carriers in semiconductors and the processes involved have attracted the attention of researchers from the fundamental point of view but are also very important for the functioning of electronic and optoelectronic semiconductor devices. A few researchers have studied the relaxation dynamics of a nonequilibrium population in the presence of equilibrium carrier..