Determination of Carrier Density and Dynamics via Magnetoelectroluminescence Spectroscopy in Resonant-Tunneling Diodes

We study the magneto-transport and magnetoelectroluminescence properties of purely $n$-doped ${\mathrm{Ga}\mathrm{As}/\mathrm{Al}}_{0.6}{\mathrm{Ga}}_{0.4}\mathrm{As}$ resonant-tunneling diodes with an ${\mathrm{In}}_{0.15}{\mathrm{Ga}}_{0.85}\mathrm{As}$ quantum well and an emitter prewell. Before the resonant-current condition, magneto-transport measurements reveal charge-carrier densities comparable for diodes with and without the emitter prewell. Landau-level splitting is observed in the electroluminescence emission from the emitter prewell, enabling the determination of the charge-carrier buildup. Our findings show that magnetoelectroluminescence spectroscopy techniques provide useful insights into the charge-carrier dynamics in resonant-tunneling diodes and comprise a versatile tool to complement magneto-transport techniques. This approach might pave the way for the development of potentially more efficient optoelectronic resonant-tunneling devices by, e.g., monitoring voltage-dependent charge accumulation for the improvement of built-in fields and hence the maximization of the photodetector efficiency and/or the minimization of optical losses.