Photocurrent Enhancement by a Polariton Condensate

We show that a condensate of exciton-polaritons greatly increases the current through a GaAs/AlAs device. These polaritons are bosons that result from coupling trapped microcavity photons with quantum well excitons. This effectively results in photons that have been dressed with mass and repulsive interactions, allowing them to undergo Bose-Einstein condensation. We fabricated ≈100 μm × 100 μm square pillars to confine the polaritons [1], and then drove in-plane current through the polariton region by placing contacts on opposite sides of the pillars. The use of identical contacts on both sides resulted in an n-i-n structure, allowing injection of only free electrons. In addition to current enhancement, we also observed stimulated injection of free carriers into polariton condensates trapped in these pillars, resulting in greatly increased polariton density.

[1] D. Myers et al, Appl. Phys. Lett. 110, 211104 (2017).