المؤلفون: Lu, C. J., Li, Chao, Zhang, Y. C., Ye, W. N., Shan, F. K., Xia, L. H.

المصدر: Journal of Applied Physics; Dec2009, Vol. 106 Issue 11, p113532-1-113532-4, 4p, 3 Black and White Photographs, 1 Diagram

مصطلحات موضوعية: THIN films, DISSOCIATION (Chemistry), EPITAXY, LANTHANUM compounds, TRANSMISSION electron microscopy, HIGH resolution electron microscopy

مستخلص: Three types of dissociated misfit dislocations (MDs) in epitaxial Ba0.3Sr0.7TiO3 thin films grown on (001) LaAlO3 have been studied by high-resolution transmission electron microscopy. First, a MD with b=[101] dissociates into two edge partials and results in the incline of film lattice. Second, a [110] MD is split into two (1/2)[110] partials of mixed character. In the third case, a [110] MD of mixed character is composed of three partials which are reacted with two (1/2)<110> stacking faults. Neither of the three types of dissociation reactions has been reported before for MDs in perovskite thin films. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of Applied Physics is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Shan, F. K., Liu, G. X., Lee, W. J., Shin, B. C.

المصدر: Journal of Applied Physics; 3/1/2007, Vol. 101 Issue 5, p053106-N.Pag, 8p, 1 Diagram, 1 Chart, 10 Graphs

مصطلحات موضوعية: THIN films, EPITAXY, SAPPHIRES, PULSED laser deposition, TEMPERATURE, SPECTROMETERS

مستخلص: ZnO thin films were epitaxial deposited on sapphire (0001) substrates at various temperatures by using the pulsed laser deposition (PLD) technique. An x-ray diffractometer (XRD) was used to investigate the structural properties of the thin film. It was found that all of the thin films were (0002) oriented and the intensity of (0002) peak increased with the increasing growth temperature. The [lowercase_phi_synonym]-scans for the thin films indicated that the thin film grown at a temperature higher than 400 °C had an epitaxial relation with the substrate. An atomic force microscope (AFM) was used to investigate the surface morphologies of the thin films. The surface roughness and grain size of the thin films increased with increasing growth temperature. A double-beam spectrophotometer was used to measure the transmittances of the thin films. The band gap energies of the thin films were calculated by linear fitting the absorption edges for high-quality thin films. A spectrometer was used to investigate the photoluminescent (PL) properties of the thin films. It was discovered that all of the thin films showed two emissions. One was the near band edge (NBE) emission; the other was the broad deep-level (DL) emission. After checking the PL of the thin films on a different date, the aging effect of the ZnO thin film on the sapphire substrate deposited by PLD was observed. It was revealed that, the NBE emissions were enhanced and the DL emissions were decreased with time. To find the reason why the DL emission decreased with time, the as-deposited thin films were annealed at 800 °C in a N2 and O2 atmosphere for 30 min, respectively. The surface morphologies and the transmittances of the annealed thin films were investigated by the AFM and spectrophotometer. The surface roughness and the transmittance decreased much after annealing. The PL measurements for the annealed thin films indicated that, the DL emission of the thin film annealed in N2 was enhanced and that annealed in O2 was quenched. It was suggested that the oxygen vacancies, instead of zinc interstitials, played the most important role for DL emissions in ZnO thin films deposited by PLD. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of Applied Physics is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Shan, F. K., Liu, G. X., Lee, W. J., Lee, G. H., Kim, I. S., Shin, B. C.

المصدر: Journal of Applied Physics; 7/15/2005, Vol. 98 Issue 2, p023504, 6p, 1 Color Photograph, 1 Black and White Photograph, 1 Chart, 9 Graphs

مصطلحات موضوعية: THIN films, SILICON, SAPPHIRES, OPTICAL diffraction, SPECTROPHOTOMETERS, ELLIPSOMETRY, REFRACTIVE index

مستخلص: Gallium oxide (Ga2O3) thin films were deposited on silicon (100) and sapphire (001) substrates using the plasma-enhanced atomic layer deposition (PEALD) technique with an alternating supply of reactant source, [(CH3)2GaNH2]3, and oxygen plasma. The thin films were annealed at different temperatures (500, 700, and 900 °C, respectively) in a rapid thermal annealing system for 1 min. It was found that Ga2O3 thin films deposited by PEALD showed excellent step coverage characteristics. X-ray diffraction measurements showed that the as-deposited thin film was amorphous. However, the thin films annealed at temperatures higher than 700 °C showed a (400) orientation of the monoclinic structure. An atomic force microscope was used to investigate the surface morphologies of the thin films. The thin films showed very smooth surfaces; the roughness of the as-deposited thin film was about 4 Å. With increasing annealing temperature, the thin film became rougher compared with that annealed at lower temperatures. A double-beam spectrophotometer was used to measure the transmittances of the thin films on the sapphire substrates. The thin films showed a very high transmittance (nearly 100%). The band-gap energies of the thin films were determined by a linear fit of the transmittance spectra and were calculated to be between 5.0 and 5.24 eV. The electrical properties of thin films of Pt/film/Si structure were also investigated. It was found that, with increasing annealing temperature, the insulating characteristics of the Ga2O3 thin films were significantly improved. Spectroscopic ellipsometry was used to derive the refractive indices and the thicknesses of the thin films. The refractive indices of the thin films showed normal dispersion behavior. The refractive indices of the thin films annealed at low temperatures were smaller than those annealed at high temperatures. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of Applied Physics is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Shan, F K., Kim, B. I., Liu, G. X., Liu, Z. F., Sohn, J. Y., Lee, W. J., Shin, B. C., Yu, Y. S.

المصدر: Journal of Applied Physics; 5/1/2004, Vol. 95 Issue 9, p4772-4776, 5p, 7 Graphs

مصطلحات موضوعية: ZINC oxide thin films, X-ray diffractometers, LATTICE dynamics, SPECTROPHOTOMETERS, PHOTOLUMINESCENCE, THIN films

مستخلص: Pure and Mg doped ZnO thin films were deposited at 400 °C on glass substrates by pulsed laser deposition. An x-ray diffractometer (XRD) was used to investigate the structural properties of the thin films. It is found that all the thin films have a preferred (002) orientation. The peak position of (002) orientation is found to shift from 34.39° to 34.55°. The lattice constants of ZnO thin films were also obtained from XRD data. It is found that, with the increase of the dopant concentration, the lattice constant a decreases from 3.25 to 3.23 Å, and c decreases from 5.20 to 5.16 Å. From the spectrophotometer transmittance data, the band gap energies of the thin films were calculated by a linear fitting process. The band gap energy of Mg doped ZnO thin film increases with increasing dopant concentration. In photoluminescence (PL) spectra, two PL emission peaks are found in pure ZnO thin films, one is the near band edge (NBE) emission at 3.28 eV, and the other is green-yellow-red emission at around 2.4 eV. However, with the increase of the dopants, no green-yellow-red emissions are found in PL of Mg doped ZnO thin films. The NBE emission has a blueshift compared with that of pure ZnO thin film (as much as 0.12 eV). As time goes on, NBE emission in pure ZnO thin film is enhanced, and the green-yellow-red emissions disappear. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

: Copyright of Journal of Applied Physics is the property of American Institute of Physics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

المؤلفون: Shan, F. K., Liu, G. X., Lee, W. J., Lee, G. H., Kim, I. S., Shin, B. C.

المصدر: Applied Physics Letters; 7/18/2005, Vol. 87 Issue 3, p039902, 1p, 1 Graph

مصطلحات موضوعية: THIN films

مستخلص: Presents a correction to the article "Aging Effect and Origin of Deep-Level Emission in ZnO Thin Film Deposited by Pulsed Laser Deposition," published online in the July 13, 2005 issue of the journal "Applied Physics Letters."