Luminescent amorphous silicon carbide ultrafine nanoparticles fabricated by pulsed-laser ablation

2017 ◽  
Vol 123 (4) ◽  
Author(s):  
Jun Zhu ◽  
Shan Hu ◽  
Wei Wang ◽  
Wei-wei Xia ◽  
Hai-tao Chen ◽  
...  
1998 ◽  
Vol 332 (1-2) ◽  
pp. 290-294 ◽  
Author(s):  
Fortunato Neri ◽  
Sebastiano Trusso ◽  
Cirino Vasi ◽  
Francesco Barreca ◽  
Paolo Valisa

1996 ◽  
Vol 11 (8) ◽  
pp. 1979-1986 ◽  
Author(s):  
Andrew L. Yee ◽  
H. C. Ong ◽  
Fulin Xiong ◽  
R. P. H. Chang

The influence of nitrogen on amorphous silicon carbide films deposited at room temperature using pulsed laser ablation has been investigated. Depositions were carried out either in ultrahigh vacuum or in a nitrogen ambient ranging from 10 to 100 mT. The mechanical and optical properties, as well as composition and structure of the resulting films, were evaluated using a variety of analytical techniques. Vacuum-deposited films exhibited high hardness but suffered from high compressive stresses (>1 GPa). At low nitrogen background pressures (<30 mT), films with an optimum balance among hardness (∼16 GPa), adhesion, and intrinsic stress (<220 MPa) were found, making them ideal candidates for protective coating applications. As nitrogen pressure was increased, mechanical performance degraded due to the increasing amount of SiO2 found in the films as evidenced by spectroscopic ellipsometry, infrared spectroscopy, and Auger electron spectroscopy measurements. The source of oxygen is attributed to residual water vapor present in our vacuum system. Optical emission spectroscopy was used to confirm the presence of Si–O species in the laser-induced plasma plume.


Author(s):  
M. Grant Norton ◽  
C. Barry Carter

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.


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