Investigation on the Photocurrent Decay Kinetics in Polyenes

Abstract

The photoconductivity decay in a number of polyene crystals has been studied. Two photocarrier decay mechanisms have been observed. A fast decay has been observed in a short time domain whereas in a longer time domain, a slow decay is manifested. Most of the photocurrent decays in the shorter time domain. The decay in the shorter time domain is dominant shallow trap limited, and the trap depth has been obtained from the activation energy of mean decay time, τ0. Field and temperature dependence studies in the longer time domain reveal the existence of additional traps distributed exponentially in some polyenes. T c, the exponential trap distribution parameter, changes with applied field, but there is no appreciable change with sample temperature. Field effect on T c has been attributed to the field effect on its trapping rate.