Charge trapping in a double quantum well system

Abstract

The effect of charge trapping in a double quantum well system is studied by undertaking transport measurements at 1.2 K as a function of front gate voltage. On sweeping the gate bias between −0.2 and 0.6 V, the trapping of electrons in the defect levels induced by the AlGaAs barrier is complemented by the decrease in the overall carrier density in the quantum well. The charging of these defect levels increases the scattering potential and enhances the overall resistance of the two dimensional electron gas. The trapped charges were completely depleted on reverse sweeping the gate bias to −0.1 V. The charging and discharging of the defect levels gave rise to a hysteresis effect in the transport measurements.