Photoluminescence spectroscopy of the low-density two-dimensional electron system in electric fields

We performed photoluminescence (PL) measurements of the two-dimensional electron system (2DES) in an undoped GaAs quantum well (QW) while controlling the electron density and electric field independently. We compared the PL spectrum at the same electron density but at different electric fields. The PL linewidth changes with electric field at low electron density below 4×1010 cm−2, but does not change with electric field at higher electron density. The sample we used is composed of a metallic mesh front gate with a 500-nm pitch. The phenomena we report here mainly originate from the longitudinal electric field bias and are commonly observed in a different-mesh-size sample.