Long-lived excitons in GaN/AlN nanowire heterostructures

Abstract

GaN/AlN nanowire heterostructures can display photoluminescence (PL) decay times on the order of microseconds that persist up to room temperature. Doping the GaN nanodisk insertions with Ge can reduce these PL decay times by two orders of magnitude. These phenomena are explained by the three-dimensional electric field distribution within the GaN nanodisks, which has an axial component in the range of a few MV/cm associated to the spontaneous and piezoelectric polarization, and a radial piezoelectric contribution associated to the shear components of the lattice strain. At low dopant concentrations, a large electron-hole separation in both the axial and radial directions is present. The relatively weak radial electric fields, which are about one order of magnitude smaller than the axial fields, are rapidly screened by doping. This bidirectional screening leads to a radial and axial centralization of the hole underneath the electron, and consequently, to large decreases in PL decay times, in addition to luminescence blue shifts.

References in corpus (7)

• Spontaneous polarization and piezoelectric constants of III-V nitrides
• A growth diagram for plasma-assisted molecular beam epitaxy of GaN nanocolumns on Si(111)
• Growth and optical properties of GaN/AlN quantum wells
• Carrier Confinement in GaN/AlGaN Nanowire Heterostructures for 0 < x <= 1
• Stark effect in GaN/AlN nanowire heterostructures: Influence of strain relaxation and surface states
• Coupling of exciton states as the origin of their biexponential decay dynamics in GaN nanowires
• Screening of the quantum-confined Stark effect in AlN/GaN nanowire superlattices by Germanium doping

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• Tuning of the Quantum-Confined Stark Effect in Wurtzite $[000\bar{1}]$ Group-III-Nitride Nanostructures by the Internal-Field-Guarded-Active-Region Design
• Assessment of AlGaN/AlN superlattices on GaN nanowires as active region of electron-pumped ultraviolet sources
• Elastic vs. plastic strain relaxation in coalesced GaN nanowires: an x-ray diffraction study
• Applications of quantum dots to the treatment of retinitis related disorders