Formation of Luminescent Si Nanocrystals by High-Temperature Annealing of Ion-Beam-Sputtered Si/SiO2 Multilayers

2003 ◽  
Vol 775 ◽  
Author(s):  
Suk-Ho Choi ◽  
Jun Sung Bae ◽  
Kyung Jung Kim ◽  
Dae Won Moon

AbstractSi/SiO2 multilayers (MLs) have been prepared under different deposition temperatures (TS) by ion beam sputtering. The annealing at 1200°C leads to the formation of Si nanocrystals in the Si layer of MLs. The high resolution transmission electron microscopy images clearly demonstrate the existence of Si nanocrystals, which exhibit photoluminescence (PL) in the visible range when TS is ≥ 300°C. This is attributed to well-separation of nanocrystals in the higher-TS samples, which is thought to be a major cause for reducing non-radiative recombination in the interface between Si nanocrystal and surface oxide. The visible PL spectra are enhanced in its intensity and are shifted to higher energy by increasing TS. These PL behaviours are consistent with the quantum confinement effect of Si nanocrystals.

2004 ◽  
Vol 817 ◽  
Author(s):  
Kang-Joo Lee ◽  
Tae-Dong Kang ◽  
Hosun Lee ◽  
Seung Hui Hong ◽  
Suk-Ho Choi ◽  
...  

AbstractUsing variable-angle spectroscopic ellipsometry, we measure the pseudo-dielectric functions of as-deposited and annealed SiO2/SiOx multilayers (MLs). The SiO2(2nm)/SiOx(2nm) MLs have been prepared under various deposition temperature by ion beam sputtering. The annealing at temperatures ≥ 1100°C leads to the formation of Si nanocrystals (nc-Si) in the SiOx layer of MLs. Transmission electron microscopy images clearly demonstrate the existence of nc-Si. We assume a Tauc-Lorentzian lineshape for the dielectric function of nc-Si, and use an effective medium approximation for SiO2/nc-Si MLs as a mixture of nc-Si and SiO2. We successfully estimate the dielectric function of nc-Si and its volume fraction. We find that the volume fraction of nc-Si decreases after annealing, with increasing x in as-deposited SiOx layer. This result is compared to expected nc-Si volume fraction, which was estimated from stoichiometry of SiOx.


Author(s):  
A.E.M. De Veirman ◽  
F.J.G. Hakkens ◽  
W.M.J. Coene ◽  
F.J.A. den Broeder

There is currently great interest in magnetic multilayer (ML) thin films (see e.g.), because they display some interesting magnetic properties. Co/Pd and Co/Au ML systems exhibit perpendicular magnetic anisotropy below certain Co layer thicknesses, which makes them candidates for applications in the field of magneto-optical recording. It has been found that the magnetic anisotropy of a particular system strongly depends on the preparation method (vapour deposition, sputtering, ion beam sputtering) as well as on the substrate, underlayer and deposition temperature. In order to get a better understanding of the correlation between microstructure and properties a thorough cross-sectional transmission electron microscopy (XTEM) study of vapour deposited Co/Pd and Co/Au (111) MLs was undertaken (for more detailed results see ref.).The Co/Pd films (with fixed Pd thickness of 2.2 nm) were deposited on mica substrates at substrate temperatures Ts of 20°C and 200°C, after prior deposition of a 100 nm Pd underlayer at 450°C.


2005 ◽  
Vol 478 (1-2) ◽  
pp. 116-120 ◽  
Author(s):  
Jae Kwon Kim ◽  
Kyu Man Cha ◽  
Jung Hyun Kang ◽  
Yong Kim ◽  
Jae-Yel Yi ◽  
...  

2010 ◽  
Vol 63 ◽  
pp. 392-395
Author(s):  
Yoshifumi Aoi ◽  
Satoru Furuhata ◽  
Hiromi Nakano

ZrN/TiN multi-layers were synthesized by ion beam sputtering technique. Microstructure and mechanical property of the ZrN/TiN multi-layers were characterized and the relationships between microstructure and hardness of the ZrN/TiN multi-layers with various bilayer thicknesses and thickness ratios were investigated. The microstructure of multi-layers have been investigated using transmission electron microscope (TEM) and X-ray diffraction (XRD).


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sung Kim ◽  
Dong Hee Shin ◽  
Dong Yeol Shin ◽  
Chang Oh Kim ◽  
Jae Hee Park ◽  
...  

During the past several decades, Si nanocrystals (NCs) have received remarkable attention in view of potential optoelectronic device applications. This paper summarizes recent progress in the study of luminescence from Si NCs, such as photoluminescence (PL), cathodoluminescence, time-solved PL, and electroluminescence. The paper is especially focused on Si NCs produced by ion beam sputtering deposition ofSiOxsingle layer orSiOx/SiO2multilayers and subsequent annealing. The effects of stoichiometry (x) and thickness of SiOxlayers on the luminescence are analyzed in detail and discussed based on possible mechanisms.


2010 ◽  
Vol 121-122 ◽  
pp. 52-57
Author(s):  
Shih Wei Mao ◽  
Jung Hsiung Shen ◽  
Der Shin Gan ◽  
Hsing Lu Huang ◽  
Sung Wei Yeh

Temperature dependent oriented growth of ZnO thin film deposited on NaCl (001) substrates using ion beam sputtering was studied by transmission electron microscopy (TEM). Thin films showing a texture due to parallel epitaxy with NaCl (001) as deposited at 100 oC, whereas thin films deposited at 400 oC can form a texture. The microstructure and the epitaxial relationship with the NaCl (001) plane were studied by a high-resolution TEM. The possible causes for the orientation changed with temperature are discussed. The optical transparency of the nanofilms grown from room temperature to 400 oC was measured.


Author(s):  
G.J.C. Carpenter ◽  
J.A. Jackman ◽  
J. McCaffrey

Argon ion sputtering is widely used in the final thinning stage for the preparation of thin foils for transmission electron microscopy. During a recent study of a titanium alloy, we observed that ion-beam thinning resulted in specimens that appeared in the electron microscope to have become severely damaged. Similar microstructures had been observed previously in zirconium, thinned in this manner. Because ion-beam sputtering takes place on the atomic scale, it seemed unlikely that gross distortion of a thin foil could have been caused directly by the sputtering process. A more detailed study has therefore been made of this phenomenon.


Author(s):  
Shang Hsien Rou

New and interesting physical phenomena are being observed via thin film depositions using a variety of processing techniques in different material systems. The present study describes Pb-Zr-Ti-O pyrochlore thin films which were deposited onto (100) MgO substrates using an ion beam sputtering technique. These films are of interest because of their unique microstructure which may provide valuable information in better understanding the epitaxial growth of thin films. Characterization were performed using conventional transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Special TEM sample preparation procedures have been developed, which will be reported elsewhere.The as-deposited pyrochlore thin film is near epitaxial and is oriented with both (100) and (111) parallel to the (100) of the MgO substrate. Figure 1(a) shows the selected area diffraction pattern (SADP) of the pyrochlore thin film taken parallel to the [100] zone axis of the substrate.


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