共查询到20条相似文献,搜索用时 15 毫秒
1.
J. Sun J.D. Wu Z.F. Ying W. Shi Z.Y. Zhou K.L. Wang X.M. Ding F.M. Li 《Applied Physics A: Materials Science & Processing》2001,73(1):91-95
Combination of pulsed laser ablation with electron cyclotron resonance microwave discharge was demonstrated for a novel method
for low-temperature thin film growth. Aluminum nitride thin films were synthesized on silicon substrates at temperatures below
80 °C by means of reactive pulsed laser deposition in nitrogen plasma generated from the electron cyclotron resonance discharge.
The synthesized films show a very smooth surface and were found to have a stoichiometric AlN composition. X-ray photoelectron
spectroscopy analysis evidenced the formation of aluminum nitride compound. Fourier transform infrared spectroscopy revealed
the characteristic phonon modes of AlN. The AlN films were observed to be highly transparent in the visible and near-IR regions
and have a sharp absorption edge near 190 nm. The band gap of the synthesized AlN films was determined to be 5.7 eV. The mechanisms
responsible for the low-temperature film synthesis are also discussed in the paper. The nitrogen plasma facilitates the nitride
formation and enhances the film growth.
Received: 17 March 2000 / Accepted: 28 March 2000 / Published online: 23 May 2001 相似文献
2.
H. Minami D. Manage Y.Y. Tsui R. Fedosejevs M. Malac R. Egerton 《Applied Physics A: Materials Science & Processing》2001,73(5):531-534
We have compared the quality of carbon films deposited with magnetically guided pulsed laser deposition (MGPLD) and conventional
pulsed laser deposition (PLD). In MGPLD, a curved magnetic field is used to guide the plasma but not the neutral species to
the substrate to deposit the films while, in conventional PLD, the film is deposited with a mixture of ions, neutral species
and clusters. A KrF laser pulse (248 nm) was focused to intensities of 10 GW/cm2 on a carbon source target and a magnetic field strength of 0.3 T was used to steer the plasma around a curved arc to the
deposition substrate. Electron energy loss spectroscopy was used in order to measure the fraction of sp3 bonding in the films produced. It is shown that the sp3 fraction, and hence the diamond-like character of the films, increased when deposited only with the pure ion component by
MGPLD compared with films produced by the conventional PLD technique. The dependence of film quality on the laser intensity
is also discussed.
Received: 7 December 2000 / Accepted: 20 August 2001 / Published online: 2 October 2001 相似文献
3.
N. D. Scarisoreanu G. Dinescu R. Birjega M. Dinescu D. Pantelica G. Velisa N. Scintee A. C. Galca 《Applied Physics A: Materials Science & Processing》2008,93(3):795-800
SBN thin films were grown on MgO and Silicon substrates by PLD and RF-PLD (radiofrequency assisted PLD) starting from single
crystal Sr0.6Ba0.4Nb2O6 and ceramic Sr0.5Ba0.5Nb2O6 stoichiometric targets. Morphological and structural analyses were performed on the SBN layers by AFM and XRD and optical
properties were measured by spectroellipsometry. The films composition was determined by Rutherford Backscattering Spectrometry.
The best set of experimental conditions for obtaining crystalline, c-axis preferential texture and with dominant 31° in-plane orientation relative to the MgO (100) axis is identified. 相似文献
4.
I. Marozau A. Shkabko G. Dinescu M. Döbeli T. Lippert D. Logvinovich M. Mallepell A. Weidenkaff A. Wokaun 《Applied Physics A: Materials Science & Processing》2008,93(3):721-727
Perovskite-type nitrogen substituted SrTiO3 thin films were deposited with a one-step process by RF-plasma assisted pulsed laser deposition from a SrTiO3 target using a N2 plasma, while deposition with a NH3 plasma yields films with almost no incorporated nitrogen. The deposited films exhibit a cubic perovskite-type crystal structure and reveal oriented growth on MgO(100) substrates. The unit cell parameters of the studied N-doped SrTiO3 films range within 3.905<a<3.918 Å, which is slightly larger than for SrTiO3 (a=3.905 Å). The nitrogen content in the deposited films varies from 0.2 to 0.7 atom%. The amount of incorporated nitrogen in the films decreases with increasing RF-power, while the N2 flow rate does not have any pronounced influence on the N content. Nitrogen incorporation results in an increased optical absorption at 400–600 nm, which is associated with N(2p) energy states that have a higher energy level than the valence band in strontium titanate. The optical band gap energies in the studied N-doped SrTiO3 films are at 3.2–3.3 eV, which is very similar to that of pure strontium titanate (~3.2 eV). Films deposited with NH3 for the RF-plasma exhibit a lower degree of crystallinity and reveal almost no nitrogen incorporation into the crystal lattice. 相似文献
5.
Synthesis of carbon nitride films by direct current plasma assisted pulsed laser deposition 总被引:1,自引:0,他引:1
Y.H. Cheng X.L. Qiao J.G. Chen Y.P. Wu C.S. Xie S.B. Muo Y.B. Sun B.K. Tay 《Applied Physics A: Materials Science & Processing》2002,74(2):225-231
Carbon nitride films were deposited by pulsed laser ablation of a graphite target under a nitrogen atmosphere at room temperature.
A direct current discharge apparatus was used to supply active nitrogen species during the deposition of carbon nitride films.
The composition and bonding structure of carbon nitride films were determined by Fourier-transform infrared (FTIR) spectroscopy
and X-ray photoelectron spectroscopy. The incorporation of nitrogen atoms in the films is greatly improved by the using of
a dc glow discharge. The ratio N/C can reach 0.34 at the discharge voltage of 400 V. Six peaks centered at 1025 cm-1, 1226 cm-1, 1381 cm-1, 1534 cm-1, 1629 cm-1, and 2200 cm-1 can be clearly distinguished from the FTIR spectra of the deposited films, which indicates the existence of C–N, C=N, and
C≡N bonds. The fraction of sp2 C, C≡N bonds, and C=N bonds in the deposited films increases with increasing discharge voltage. Deconvolution results of
C 1s and N 1s spectra also indicate that nitrogen atoms in the films are chemically bonded to sp1 C, sp2 C, and sp3 C atoms. Most of the nitrogen atoms are bonded to sp2 C atoms. Increasing the discharge voltage leads to a decrease of the fraction of nitrogen atoms bonded to sp2 C and the fraction of amorphous carbon; however, it leads to an increase of the fraction of nitrogen atoms bonded to sp3 C and the fraction of sp2 C and sp3 C atoms bonded to nitrogen atoms.
Received: 7 June 2000 / Accepted: 19 February 2001 / Published online: 27 June 2001 相似文献
6.
D.M. Bubb B. Toftmann R.F. Haglund Jr. J.S. Horwitz M.R. Papantonakis R.A. McGill P.W. Wu D.B. Chrisey 《Applied Physics A: Materials Science & Processing》2002,74(1):123-125
Thin films of the biodegradable polymer poly(DL-lactide-co-glycolide) (PLGA) were deposited using resonant infrared pulsed
laser deposition (RIR-PLD). The output of a free-electron laser was focused onto a solid target of the polymer, and the films
were deposited using 2.90 (resonant with O-H stretch) and 3.40 (C-H) μm light at macropulse fluences of 7.8 and 6.7 J/cm2, respectively. Under these conditions, a 0.5-μm thick film can be grown in less than 5 min. Film structure was determined
from infrared absorbance measurements and gel permeation chromatography (GPC). While the infrared absorbance spectrum of the
films is nearly identical with that of the native polymer, the average molecular weight of the films is a little less than
half that of the starting material. Potential strategies for defeating this mass change are discussed.
Received: 22 August 2001 / Accepted: 23 August 2001 / Published online: 17 October 2001 相似文献
7.
L. Barbadillo F.J. Gómez M.J. Hernández J. Piqueras 《Applied Physics A: Materials Science & Processing》1999,68(5):603-607
Electron cyclotron resonance plasma chemical vapor deposition with nitrogen, methane, and argon-diluted silane as precursors
has been used to prepare SiCN thin films. Optical emission from CN species in the plasma has been observed. Infrared measurements
show that most of the nitrogen is incorporated to the thin solid films in the form of Si-N, C=N and C≡N bonds suggesting a
basic structure of incomplete SiN tetrahedra with C=N and C≡N bridging bonds. The deposited films are nearly transparent in
the visible range with a weak absorption threshold between 2.2 and 3.5 eV.
Received: 3 April 1998 / Accepted: 5 January 1999 / Published online: 31 March 1999 相似文献
8.
采用电子回旋共振等离子体化学气相淀积(ECR-CVD)法,以C4F8和CH4为源气体制备了非晶氟化碳(a-C:F)薄膜.X射线电子能谱(XPS)和傅里叶变换红外光谱(FTIR)分析表明,a-C:F薄膜退火后厚度减小是由于位于a-C:F薄膜交联结构末端的C—C和CF3结合态的热稳定性较差,导致退火时容易生成气态挥发物造成的.a-C:F膜介电常数在300℃氮气气氛中退火后由于电子极化增大和薄膜密度增加而上升,界面态陷阱密度从(5—9)×1011eV-1·cm-2降至(4—6)×1011eV-1·cm-2.a-C:F薄膜导电行为在低场强区域呈现欧姆特性,在高场强区域符合 Poole-Frankel机理.非定域π电子在带尾形成陷阱且陷阱能量在退火后降低,从而使更多陷阱电子在场增强热激发作用下进入导带并引起电流增大.
关键词:
a-C:F
ECR-CVD
键结构
电学性质 相似文献
9.
K. Yamamoto Y. Koga S. Fujiwara F. Kokai R.B. Heimann 《Applied Physics A: Materials Science & Processing》1998,66(1):115-117
3 bonds in the carbon films prepared by pulsed laser deposition of carbon obtained from graphite was investigated by electron
energy loss spectroscopy (EELS) and X-ray photoelectron spectroscopy (XPS). The fraction of sp3 bonds increased with a decreasing laser wavelength. Energetic C+ ion species were effectively produced by using a short-wavelength laser. The sp3 bond fraction increased with an increasing amount of energetic C+ ion species. The fractions of sp3 bonds in the carbon film were 80%, 42%, 26% and 15% at wavelengths of 193, 248, 532 and 1064 nm, respectively.
Received: 28 October 1997/Accepted:29 October 1997 相似文献
10.
O.M. Hussain K. Srinivasa Rao K.V. Madhuri C.V. Ramana B.S. Naidu S. Pai J. John R. Pinto 《Applied Physics A: Materials Science & Processing》2002,75(3):417-422
Molybdenum trioxide thin films were prepared by reactive pulsed laser deposition on Corning 7059 glass substrates. The influence
of oxygen partial pressure and deposition temperature on the structure, surface morphology and optical properties of these
films was studied to understand the growth mechanism of MoO3 thin films. The films formed at 473 K in an oxygen partial pressure of 100 mTorr exhibited predominantly a (0k0) orientation,
corresponding to an orthorhombic layered structure of α-MoO3. The evaluated optical band gap of the films was 3.24 eV. The crystallite size increased with increase of deposition temperature.
The films formed at an oxygen partial pressure of pO2=100 mTorr and at a deposition temperature greater than 700 K exhibited both (0k0) and (0kl) orientations, representing α-β
mixed phases of MoO3. The films formed at an oxygen partial pressure less than 100 mTorr were found to be sub-stoichiometric with α-β mixed phases.
The investigation revealed the growth of polycrystalline and single-phase orthorhombic-layered-structure α-MoO3 thin films with composition nearly approaching the nominal stoichiometry at moderate substrate temperatures in an oxygen
partial pressure of 100 mTorr.
Received: 9 April 2001 / Accepted: 6 August 2001 / Published online: 17 October 2001 相似文献
11.
For the first time, barium ferrite films with in-plane orientation were prepared at 700°C by pulsed laser deposition technique (PLD) on Si(1 1 1) without any post-annealing. An amorphous Ba–Fe–O film is used as underlayer to facilitate the crystallization and improve the orientation of films. Sharp (1 1 0) and (2 2 0) peaks appeared in the XRD pattern. The surface morphologies observed by SEM are similar to the typical computer generated grain arrangements obtained by Suzuki et al. in their micromagnetics study. Furthermore, a particular kind of structure of film cross-section was identified in PLD for barium ferrite films. The grain size is about 3 μm, and the coercivity is around 1500 Oe. 相似文献
12.
Y. Du M.-S. Zhang J. Wu L. Kang S. Yang P. Wu Z. Yin 《Applied Physics A: Materials Science & Processing》2003,76(7):1105-1108
SrTiO3 thin films were prepared on a fused-quartz substrate by pulsed laser deposition (PLD). Dense and homogeneous films with a
thickness of 260 nm were prepared. Optical constants (refractive index n and extinction coefficient k) were determined from
the transmittance spectra using the envelope method. The optical band gap energy of the films was found to be 3.58 eV, higher
than the 3.22 eV for bulk SrTiO3, attributable to the film stress exerted by the substrate. The dispersion relation of the refractive index vs. wavelength
follows the single electronic oscillator model. The refractive index and the packing density for the PLD-prepared SrTiO3 thin films are higher than those for the SrTiO3 films prepared by physical vapor deposition, sol–gel and RF sputtering.
Received: 18 March 2002 / Accepted: 7 October 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: mszhang@nju.edu.cn 相似文献
13.
Martin Pavlišta Martin Hrdlička Petr Němec Jan Přikryl Miloslav Frumar 《Applied Physics A: Materials Science & Processing》2008,93(3):617-620
Amorphous chalcogenide thin films were prepared from As2Se3, As3Se2 and InSe bulk glasses by pulsed laser deposition using a KrF excimer laser. Thickness profiles of the films were determined
using variable angle spectroscopic ellipsometry. The influence of the laser beam scanning process during the deposition on
the thickness distribution of the prepared thin films was evaluated and the corresponding equations suggested. The results
were compared with experimental data. 相似文献
14.
F. Kokai K. Yamamoto Y. Koga S. Fujiwara R.B. Heimann 《Applied Physics A: Materials Science & Processing》1998,66(4):403-406
x ) films in a nitrogen atmosphere within the range 5×10-4–4×10-1 Torr. In the presence of a magnetic field, the emission intensities of N2 (second positive system) and CN species in the graphite ablation plumes were altered significantly, depending on the pressure
of the N2 environment. Corresponding to an intense CN emission, a magnetic field-induced enhancement of N incorporation – for example,
up to 37% at an N2 pressure of 300 mTorr – and the formation of sp3 tetrahedral CN bonding were both observed in the films. This suggests that the arrival of CN species at the substrate surface
with kinetic energies is important for film deposition.
Received: 27 August 1997/Accepted: 8 September 1997 相似文献
15.
(001)-oriented strontium bismuth tantalate thin films have been grown on Pt/TiO2/SiO2/Si (100) substrates by pulsed laser deposition. The room-temperature current–electric field dependence of the films has been
investigated, which revealed a space-charge-limited conduction mechanism. The microstructures of grain boundaries and structural
defects in these films were also examined by transmission electron microscopy and high-resolution transmission electron microscopy,
respectively. The grains of the films deposited at 550 °C exhibited polyhedral morphologies, and the average grain size was
about 50 nm in length and 35 nm in width. At a small misorientation angle (8.2°) tilt boundary, a regular array of edge dislocations
with about 3-nm periodic distance was observed, and localized strain contrast near the dislocation cores was also observed.
The Burgers vector b of the edge dislocation was determined to be [110]. At a high misorientation angle (39.0°) tilt grain boundary lattice strain contrast associated with the distortion of
lattice planes was observed, and the mismatching lattice images occurred at about 2 nm along the boundary. The relationship
between microstructural defects at grain boundaries and leakage currents of these films is also discussed.
Received: 8 September 2000 / Accepted: 18 December 2000 / Published online: 28 February 2001 相似文献
16.
L. Escobar-Alarcon V. MedinaEnrique Camps S. RomeroM. Fernandez D. Solis-Casados 《Applied Surface Science》2011,257(21):9033-9037
In this work, Raman spectroscopy has been used to characterize Ti-C-N thin films in order to obtain information about the microstructure of the deposited materials, and in particular to study the effects due to the carbon incorporation into the TiN lattice. Ti-C-N thin films were prepared using a crossed plasma configuration in which the ablation of two different targets, titanium and carbon, in a reactive atmosphere was performed. With this configuration, the carbon content in the films was varied in an easy way from 5.0 at% to 40.0 at%. Thin film composition was determined from Non-Rutherford Backscattering Spectroscopy (NRBS) measurements. X-ray photoelectron spectroscopy and X-Ray diffraction measurements were also carried out in order to characterize the films in more detail, with this being used to give support to the interpretation of the Raman spectra. The Raman results revealed that at lower carbon concentrations a solid solution Ti(C, N) is formed, whilst at higher carbon concentrations a nanocomposite, consisting of nanocrystalline TiCN and TiC immersed in an amorphous carbon matrix is obtained. 相似文献
17.
J.A. Chaos J. Gonzalo C.N. Afonso J. Perrière M.T. García-González 《Applied Physics A: Materials Science & Processing》2001,72(6):705-710
Laser ablation of single-crystal LiNbO3 in a gas environment is used to grow films on (100) Si substrates heated to 650 °C. The film composition and crystallinity
are studied as a function of the nature (reactive, O2, or inert, Ar) and pressure of the gas environment applied during deposition and cooling-down processes, the laser energy
density and the target–substrate distance. Experimental results show that a gas pressure close to 1 mbar is required to produce
stoichiometric films in either O2 or Ar. The modification of the laser energy density and the target–substrate distance allows us to improve the crystallinity
of the films that become textured along the (006) direction. The influence of the experimental parameters on the film properties
is discussed in the frame of the formation of a blast wave, that leads to the focusing of the expanding Li species and thus,
to the increase of the Li content in the films.
Received: 8 February 2001 / Accepted: 9 February 2001 / Published online: 3 May 2001 相似文献
18.
SrBi2Ta2O9 (SBT) ferroelectric thin films with different preferred orientations were deposited by pulsed laser deposition (PLD). Several
methods have been developed to control the preferred orientation of SBT thin films. For SBT films deposited directly on Pt/TiO2/SiO2/Si substrates and in situ crystallized at the deposition temperature, the substrate temperature has a significant impact
on the orientation and the remnant polarization (Pr) of the films; a higher substrate temperature benefits the formation of
(115) texture and larger grain size. The films deposited on Pt/TiO2/SiO2/Si substrates at 830 °C are (115)-oriented and exhibit 2Pr of 6 μC/cm2. (115)- and (200)-predominant films can be formed by using a La0.85Sr0.15CoO3 (LSCO) buffer layer or by annealing amorphous SBT films deposited on Pt/TiO2/SiO2/Si substrates at 450 °C using rapid thermal annealing (RTA). These films exhibit good electric properties; 2Pr of the films
are up to 12 μC/cm2 and 17 μC/cm2, respectively. The much larger 2Pr of the films deposited on the LSCO buffer layer and of the films obtained by RTA than
2Pr of the films deposited on Pt/TiO2/SiO2/Si substrates at 830 °C is attributed to a stronger (200) texture.
Received: 30 January 2001 / Accepted: 30 May 2001 / Published online: 25 July 2001 相似文献
19.
A. Basillais C. Boulmer-Leborgne J. Mathias N. Laidani A. Laurent J. Perrière 《Applied Physics A: Materials Science & Processing》2000,71(6):619-625
We have studied the growth of Al nitride films by laser ablation in order to check the potential of the method. The influence
of process parameters such as nature of the target, laser energy density, nitrogen partial pressure, etc. on the composition,
chemical nature and structure of the films has been investigated. Rutherford backscattering spectrometry, nuclear reaction
analysis, X-ray diffraction and X-ray photoelectron spectroscopy were used to characterize the films. Literature reports on
AlN film growth by laser ablation but oxygen contamination is poorly discussed whereas it is the main problem encountered.
The origin of this contamination and the mechanisms of incorporation were studied, and the crucial parameter was found to
be the residual pressure during ablation. Due to the difference in chemical reactivity between oxygen and nitrogen atomic
species, to obtain pure AlN films it is necessary to increase the concentration of atomic nitrogen. Thus, a RF discharge device
was added allowing a better nitrogen molecule dissociation. Finally, despite composition deviations, the AlN phase can be
formed in the laser-deposited films. Highly textured films presenting epitaxial relationships with crystalline Al2O3 substrates can be grown even with a 10% oxygen concentration.
Received: 7 October 1999 / Accepted: 17 April 2000 / Published online: 13 September 2000 相似文献
20.
S. Heiroth Th. Lippert A. Wokaun M. Döbeli 《Applied Physics A: Materials Science & Processing》2008,93(3):639-643
Yttria-stabilized zirconia (YSZ) is the most common solid electrolyte material used e.g. in ceramic fuel cells. Thin films
of YSZ were deposited on c-cut sapphire single crystals by pulsed laser deposition using a KrF excimer laser focused on a polycrystalline 8 mol% Y2O3-stabilized ZrO2 target. Depending on the substrate temperature and the oxygen background pressure during deposition, different microstructures
are obtained. XRD and high-resolution SEM revealed the formation of dense amorphous films at room temperature. At 600°C preferentially
(111) oriented polycrystalline films consisting of densely agglomerated nm-sized grains of the cubic phase resulted. Grain
size and surface roughness could be controlled by varying the oxygen background pressure. RBS and PIXE evidenced congruent
transfer only for a low number of pulses, indicating a dynamical change of the target stoichiometry during laser irradiation.
The in-plane ionic conductivity of the as-deposited crystalline films was comparable to bulk YSZ. The conductivity of initially
amorphous YSZ passes a maximum during the crystallization process. However, the relative changes remain small, i.e. no significant
enhancement of ionic conductivity related to the formation of a nanocrystalline microstructure is found. 相似文献