title: Room-temperature photodetection dynamics of single GaN nanowires.
abstract: We report on the photocurrent behavior of single GaN n-i-n nanowires (NWs) grown by plasma-assisted molecular-beam epitaxy on Si(111). These structures present a photoconductive gain in the range of 10(5)-10(8) and an ultraviolet (350 nm) to visible (450 nm) responsivity ratio larger than 6 orders of magnitude. Polarized light couples with the NW geometry with a maximum photoresponse for polarization along the NW axis. The photocurrent scales sublinearly with optical power, following a I ~ P(β) law (β < 1) in the measured range with β increasing with the measuring frequency. The photocurrent time response remains in the millisecond range, which is in contrast to the persistent (hours) photoconductivity effects observed in two-dimensional photoconductors. The photocurrent is independent of the measuring atmosphere, either in the air or in vacuum. Results are interpreted taking into account the effect of surface states and the total depletion of the NW intrinsic region.
authors.affiliation: CEA-CNRS Group Nanophysique et Semiconducteurs, INAC-SP2M, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France. fernando.gonzalez-posada@cea.fr
authors.forename: F
authors.initials: F
authors.lastname: González-Posada
authors.forename: R
authors.initials: R
authors.lastname: Songmuang
authors.forename: M
authors.initials: M
authors.lastname: Den Hertog
authors.forename: E
authors.initials: E
authors.lastname: Monroy
mesh_terms: D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005708:Gallium / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects*; D036103:Nanotechnology / Q000295:instrumentation*; D010783:Photometry / Q000295:instrumentation*; D017785:Photons; D013696:Temperature
chemical_list: C473348:gallium nitride; D005708:Gallium