Near-field spectroscopy of a gated electron gas: a direct evidence for electrons localization

TL;DR

This study uses near-field photoluminescence to directly visualize electron localization in a gated two-dimensional electron gas, revealing spatial charge fluctuations caused by disorder.

Contribution

It provides direct imaging evidence of electron localization in a 2D electron gas using near-field spectroscopy, linking luminescence fluctuations to electron and donor distributions.

Findings

Observed large spatial fluctuations in negatively charged exciton luminescence.

Fluctuations attributed to electrons localized by random potential of ionized donors.

Successfully imaged electron and donor distributions in the plane.

Abstract

The near-field photoluminescence of a gated two-dimensional electron gas is measured. We use the negatively charged exciton, formed by binding of an electron to a photo-excited electron-hole pair, as an indicator for the local presence of charge. Large spatial fluctuations in the luminescence intensity of the negatively charged exciton are observed. These fluctuations are shown to be due to electrons localized in the random potential of the remote ionized donors. We use these fluctuations to image the electrons and donors distribution in the plane.