title: The state of strain in single GaN nanocolumns as derived from micro-photoluminescence measurements.
abstract: In the present paper, studies on the state of strain in single and ensembles of nanocolumns investigated by photoluminescence spectroscopy will be presented. The GaN nanocolumns were either grown in a bottom-up approach or prepared in a top-down approach by etching compact GaN layers grown on Si(111) and sapphire (0001) substrates. Experimental evidence for strain relaxation of the nanocolumns was found. The difference and development of the strain value for different nanocolumns could be verified by spatially resolved micro-photoluminescence on single nanocolumns separated from their substrate. A common D0X spectral position at 3.473 eV was found for all separated single GaN nanocolumns independent of the substrate or processing technique used, as expected for a relaxed system.
authors.affiliation: Institute of Thin Films and Interfaces (ISG1), CNI (Center of Nanoelectronic Systems for Information Technology), Research Center Jülich, 52425 Jülich, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Thillosen
authors.forename: Kathrin
authors.initials: K
authors.lastname: Sebald
authors.forename: Hilde
authors.initials: H
authors.lastname: Hardtdegen
authors.forename: Ralph
authors.initials: R
authors.lastname: Meijers
authors.forename: Raffaella
authors.initials: R
authors.lastname: Calarco
authors.forename: Simone
authors.initials: S
authors.lastname: Montanari
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Kaluza
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gutowski
authors.forename: Hans
authors.initials: H
authors.lastname: Lüth
mesh_terms: D004548:Elasticity; D005708:Gallium / Q000032:analysis* / Q000737:chemistry*; D008163:Luminescent Measurements; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D010316:Particle Size; D013314:Stress, Mechanical; D013718:Tensile Strength
chemical_list: C473348:gallium nitride; D005708:Gallium