title: Determination of critical diameters for intrinsic carrier diffusion-length of GaN nanorods with cryo-scanning near-field optical microscopy.
abstract: Direct measurements of carrier diffusion in GaN nanorods with a designed InGaN/GaN layer-in-a-wire structure by scanning near-field optical microscopy (SNOM) were performed at liquid-helium temperatures of 10 K. Without an applied voltage, intrinsic diffusion lengths of photo-excited carriers were measured as the diameters of the nanorods differ from 50 to 800 nm. The critical diameter of nanorods for carrier diffusion is concluded as 170 nm with a statistical approach. Photoluminescence spectra were acquired for different positions of the SNOM tip on the nanorod, corresponding to the origins of the well-defined luminescence peaks, each being related to recombination-centers. The phenomenon originated from surface oxide by direct comparison of two nanorods with similar diameters in a single map has been observed and investigated.
authors.affiliation: Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden.
authors.forename: Y T
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden.
authors.forename: K F
authors.initials: KF
authors.lastname: Karlsson
authors.affiliation: Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Birch
authors.affiliation: Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden.
authors.forename: P O
authors.initials: PO
authors.lastname: Holtz