Probing ErAs nanoparticle density of states using capacitance-voltage

Two asymmetric In$_{0.53}$Ga$_{0.47}$As/In$_{0.53}$Al$_{0.47}$As double-barrier samples are fabricated and compared using low-temperature capacitance-voltage measurements. The two samples are identical except for a layer of ErAs nanoparticles embedded within the quantum well layer of one of the samples. A clear difference in the capacitance-voltage profile is observed between the two samples, and the difference is attributed to additional available states associated with the ErAs nanoparticles. These results are compared with a charge-step simulation of the low-frequency capacitance of the device in order to estimate the density of states contributed by the ErAs nanoparticles.