An experimental demonstration of irreversible mesoscopic carrier transport phenomena in InGaN quantum wells

Light-induced carrier transport in mesoscopic systems exhibits a complex interplay between classical and quantum phenomena. Through direct spectroscopic measurements of optoelectronic energy transport in semiconductor quantum wells, we reveal the irreversible nature of carrier dynamics in the mesoscopic regime. A 2-probe near-field optical microscopy setup based on multiprobe scanning tunnelling microscopy detected the local excitation and emission at nanoscale resolution. By systematically exchanging the roles of the excitation and detection probes, we demonstrate a clear asymmetry in the spectroscopic response, indicating directional and irreversible transport behaviour. Our proposed approach directly reveals irreversible carrier transport in mesoscopic domains and can probe local excitonic dynamics, opening pathways for designing novel optoelectronic devices with irreversible transport mechanisms.