title: Single excitons in InGaN quantum dots on GaN pyramid arrays.
abstract: Fabrication of single InGaN quantum dots (QDs) on top of GaN micropyramids is reported. The formation of single QDs is evidenced by showing single sub-millielectronvolt emission lines in microphotoluminescence (μPL) spectra. Tunable QD emission energy by varying the growth temperature of the InGaN layers is also demonstrated. From μPL, it is evident that the QDs are located in the apexes of the pyramids. The fact that the emission lines of the QDs are linear polarized in a preferred direction implies that the apexes induce unidirected anisotropic fields to the QDs. The single emission lines remain unchanged with increasing the excitation power and/or crystal temperature. An in-plane elongated QD forming a shallow potential with an equal number of trapped electrons and holes is proposed to explain the absence of other exciton complexes.
authors.affiliation: Department of Physics, Chemistry and Biology (IFM), Linköping University, S-581 83, Linköping, Sweden.
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Hsu
authors.forename: Anders
authors.initials: A
authors.lastname: Lundskog
authors.forename: K Fredrik
authors.initials: KF
authors.lastname: Karlsson
authors.forename: Urban
authors.initials: U
authors.lastname: Forsberg
authors.forename: Erik
authors.initials: E
authors.lastname: Janzén
authors.forename: Per Olof
authors.initials: PO
authors.lastname: Holtz
mesh_terms: D005708:Gallium / Q000737:chemistry*; D007204:Indium / Q000737:chemistry*; D008163:Luminescent Measurements; D045663:Quantum Dots; D013696:Temperature
chemical_list: D007204:Indium; C473348:gallium nitride; D005708:Gallium; C513701:indium nitride