Comparison of the dark current from an AlGaAs/GaAs and AlGaN/GaN quantum well

摘要

Abstract: The calculation of the dark currents existing in a AlGaN/GaN quantum well IR photodetector is presented in this paper. The dark current is calculated from the electrons following from the n$+$PLU$/ region through the top barrier and not from out of the quantum well. This is a result of the number of electron emitting a quantum well equaling the number of electrons being captured, resulting in a zero net current. The calculation of the current accounts for the redistribution of the density of states and the local velocity arising form the multiple quantum well structure. A comparison of the experimental results to the theoretical calculation of the transmission coefficient, the local velocity and the density of states demonstrate that the variation in the dark currents is a result of the variation in the growth process from one structure to another and not a function of the number of quantum wells. A comparison is made between an AlGaAs/GaAs based system and an AlGaN/GaN based system demonstrating a large reduction in the dark current. !11