Exciton localization and drift in tailored-potential quantum nanowires

Abstract

Exciton recombination dynamics in tailored-potential, site-controlled AlGaAs quantum wires (QWRs) are studied. Time-resolved photoluminescence spectra evidence exciton localization in weakly disordered “uniform” QWRs, whereas deterministic bandgap grading is shown to suppress localization and promote exciton drift along the potential gradient. Measured exciton transit times between two quantum dot probes placed at opposite ends of the potential gradient yield the effective 1D exciton mobility as >1300 cm2/(eVs).

Crystal-Phase Quantum Wires: One-Dimensional Heterostructures with Atomically Flat Interfaces

“…7,8 Exciton localization in quantum structures usually occurs at local fluctuations in width and alloy content. This phenomenon has been extensively studied for quantum wells, but has also been reported for V-groove and pyramidal quantum wire heterostructures 8,9 as well as for ultrathin nanowires surrounded by air. 10 Crystal-phase bandgap engineering in semiconductor nanowires has opened the possibility to fabricate heterostructures free of such fluctuations.…”

“…Exciton localization in quantum structures usually occurs at local fluctuations in width and alloy content. This phenomenon has been extensively studied for quantum wells, but has also been reported for V-groove and pyramidal quantum wire heterostructures , as well as for ultrathin nanowires surrounded by air . Crystal-phase bandgap engineering in semiconductor nanowires has opened the possibility to fabricate heterostructures free of such fluctuations. − Crystal-phase quantum wells are induced by twin boundaries and basal plane stacking faults (BSFs) intersecting nanowires axially, but also by inversion domain boundaries (IDBs) of type IDB* running along the length of the nanowires .…”