title: Ordered YBCO sub-micron array structures induced by pulsed femtosecond laser irradiation.
abstract: We report on the formation of organized sub-micron YBa(2)Cu(3)O(7) (YBCO) dots induced by irradiating femtosecond laser pulses on YBCO films prepared by pulse laser deposition with fluence in the range of 0.21 approximately 0.53 J/cm(2). The morphology of the YBCO film surface depends strongly on the laser fluences irradiated. At lower laser fluence (approximately 0.21 J/cm(2)) the morphology was pattern of periodic ripples with sub-micrometer spacing. Slightly increasing the laser fluence to 0.26 J/cm(2) changes the pattern into organized sub-micron dots with diameters ranging from 100 nm to 800 nm and height of 150 nm. Further increase of the laser fluence to over 0.32 J/cm(2), however, appeared to result in massive melting and led to irregular morphology. The mechanism and the implications of the current findings will be discussed. Arrays of YBCO sub-micron dots with T(c) = 89.7 K were obtained.
authors.affiliation: Department of Electrophysics, National Chiao-Tung University, Hsinchu, Taiwan, ROC. cwluo@mail.nctu.edu.tw
authors.forename: C W
authors.initials: CW
authors.lastname: Luo
authors.forename: C C
authors.initials: CC
authors.lastname: Lee
authors.forename: C H
authors.initials: CH
authors.lastname: Li
authors.forename: H C
authors.initials: HC
authors.lastname: Shih
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Chen
authors.forename: C C
authors.initials: CC
authors.lastname: Hsieh
authors.forename: C H
authors.initials: CH
authors.lastname: Su
authors.forename: W Y
authors.initials: WY
authors.lastname: Tzeng
authors.forename: K H
authors.initials: KH
authors.lastname: Wu
authors.forename: J Y
authors.initials: JY
authors.lastname: Juang
authors.forename: T M
authors.initials: TM
authors.lastname: Uen
authors.forename: S P
authors.initials: SP
authors.lastname: Chen
authors.forename: J-Y
authors.initials: JY
authors.lastname: Lin
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D007834:Lasers; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D011829:Radiation Dosage