title: Quasi-one-dimensional density of states in a single quantum ring.
abstract: Generally confinement size is considered to determine the dimensionality of nanostructures. While the exciton Bohr radius is used as a criterion to define either weak or strong confinement in optical experiments, the binding energy of confined excitons is difficult to measure experimentally. One alternative is to use the temperature dependence of the radiative recombination time, which has been employed previously in quantum wells and quantum wires. A one-dimensional loop structure is often assumed to model quantum rings, but this approximation ceases to be valid when the rim width becomes comparable to the ring radius. We have evaluated the density of states in a single quantum ring by measuring the temperature dependence of the radiative recombination of excitons, where the photoluminescence decay time as a function of temperature was calibrated by using the low temperature integrated intensity and linewidth. We conclude that the quasi-continuous finely-spaced levels arising from the rotation energy give rise to a quasi-one-dimensional density of states, as long as the confined exciton is allowed to rotate around the opening of the anisotropic ring structure, which has a finite rim width.
authors.affiliation: Department of Opto-Mechatronics Engineering and Cogno-Mechatronics Engineering, Physics Education, RCDAMP, Pusan Nat'l University, Busan 609-735, Republic of Korea.|Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, U.K.
authors.forename: Heedae
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Opto-Mechatronics Engineering and Cogno-Mechatronics Engineering, Physics Education, RCDAMP, Pusan Nat'l University, Busan 609-735, Republic of Korea.
authors.forename: Woojin
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Opto-Mechatronics Engineering and Cogno-Mechatronics Engineering, Physics Education, RCDAMP, Pusan Nat'l University, Busan 609-735, Republic of Korea.
authors.forename: Seongho
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Opto-Mechatronics Engineering and Cogno-Mechatronics Engineering, Physics Education, RCDAMP, Pusan Nat'l University, Busan 609-735, Republic of Korea.
authors.forename: Kwangseuk
authors.initials: K
authors.lastname: Kyhm
authors.affiliation: Department of Physics, College of Liberal Arts and Sciences, Anyang University, Gyeonggi-do, 430-714, Republic of Korea.
authors.forename: Koochul
authors.initials: K
authors.lastname: Je
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, U.K.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Taylor
authors.affiliation: Department of NANOscience, Institut Néel, CNRS, rue des Martyrs 38054, Grenoble, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Nogues
authors.affiliation: Department of NANOscience, Institut Néel, CNRS, rue des Martyrs 38054, Grenoble, France.
authors.forename: Le Si
authors.initials: LS
authors.lastname: Dang
authors.affiliation: Center for Opto-Electronics Convergence Systems, KIST, Seoul, 136-791, Republic of Korea.
authors.forename: Jin Dong
authors.initials: JD
authors.lastname: Song