Experimental analysis of tunneling from a two-dimensional electron gas into the bulk in the presence of strong scattering.

An asymmetric double-barrier heterostructure of InGaAs/InAlAs was grown lattice-matched to InP, and electrical contact was made to the InGaAs quantum well layer as well as both bulk InGaAs regions.~ The tunnel current out of the quantum well across one barrier was monitored while varying the electric field across the other (thicker) barrier.~ This measurement yielded the dependence of the tunnel current on the carrier concentration in the quantum well.~ Samples with ErAs dot scattering centers within the quantum well were measured and compared with device simulations to confirm the impact of scattering on tunneling out of a quantum well.