scholarly journals Using Deposition Rate and Substrate Temperature to Manipulate Liquid Crystal-Like Order in a Vapor-Deposited Hexagonal Columnar Glass

2021 ◽  
Vol 125 (10) ◽  
pp. 2761-2770
Author(s):  
Camille Bishop ◽  
Zhenxuan Chen ◽  
Michael F. Toney ◽  
Harald Bock ◽  
Lian Yu ◽  
...  
2006 ◽  
Vol 527-529 ◽  
pp. 299-302
Author(s):  
Hideki Shimizu ◽  
Yosuke Aoyama

3C-SiC films grown on carbonized Si (100) by plasma-assisted CVD have been investigated with systematic changes in flow rate of monosilane (SiH4) and propane (C3H8) as source gases. The deposition rate of the films increased monotonously and the microstructures of the films changed from 3C-SiC single crystal to 3C-SiC polycrystal with increasing flow rate of SiH4. Increasing C3H8 keeps single crystalline structure but results in contamination of α-W2C, which is a serious problem for the epitaxial growth. To obtain high quality 3C-SiC films, the effects of C3H8 on the microstructures of the films have been investigated by reducing the concentration of C3H8. Good quality 3C-SiC single crystal on Si (100) is grown at low net flow rate of C3H8 and SiH4, while 3C-SiC single crystal on Si (111) is grown at low net flow rate of C3H8 and high net flow rate of SiH4. It is expected that 3C-SiC epitaxial growth on Si (111) will take placed at a higher deposition rate and lower substrate temperature than that on Si (100).


2021 ◽  
Author(s):  
Mingguang Zhu ◽  
Meihui Chen ◽  
Hongyu Guo ◽  
Fafu Yang

Abstract A novel fluorescein-bridged perylene bisimide (PBI) dimer for liquid crystal (LC) with geometrically symmetric structure was developed. The mesomorphic results indicated that the energetically stable and unstable conformers of fluorescein fragments could lead to the transformation of mesophases from a hexagonal columnar mesophase to an uncertain phase at 136.9 °C in heating, whilst a stable hexagonal columnar mesophase maintained between 175.6 °C and 58.6 °C in cooling. The selectively excited fluorescence characters in THF solution demonstrated that the fluorescence resonance energy transfer (FRET) effect between fluorescein fragments and PBI unites could provide a means to effectively impose strong fluorescence of the dimeric PBIs modified with suitable chromophore at the N-imide position, which alternatively serves as a platform for the further study of multi-functional PBI-based LCs.


1990 ◽  
Vol 187 ◽  
Author(s):  
C. S. Chang ◽  
J. C. Wang ◽  
L. C. Kuo

AbstractAn electron beam evaporation method has been used to prepare tin doped indium oxide (ITO) films with 95 wt.% In2O3 and 5 wt.% SnO2 in an oxygen atmosphere. It was found that the deposition rate and oxygen pressure strongly influence the film properties when the substrate temperature was lower than 200°C. In an optimal condition, highly transparent (transmittance ˜ 90% at wavelength 570 nm) and conductive (resistivity – 3×10−4Ω-cm) films of thickness around 2000 Å at substrate temperature as low as 180°C can be obtained.


1991 ◽  
Vol 236 ◽  
Author(s):  
Gary A. Smith ◽  
Li-Chyong Chen ◽  
Mei-Chen Chuang

AbstractSystematic experiments have been carried out to characterize the yttria containing zirconia thin films on sapphire substrates by 248nm KrF excimer laser ablation. The deposition rate as a function of laser fluence and O2 pressure at room temperature was measured with a quartz crystal microbalance. The results show different threshold fluences for deposition in vacuum vs. oxygen. While the deposition rate increases with increasing fluence at a given oxygen pressure, the rate eventually saturates at a higher laser fluence. At a given fluence, the oxygen pressure dependence of the deposition rate shows a radical reduction when the O2 pressure increases from 10 mTorr to 1 Torr. Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy were used to obtain stoichiometric information. A very strong pressure dependence of the O/Zr ratio was observed. While the trend of increasing O/Zr and Zr/Y ratio with increasing O2 pressure is apparent, the correlations between O/Zr as well as Zr/Y ratio and other processing conditions are less obvious. RBS results indicate an increasing roughness at the interface between the ZrO2 film and the sapphire substrate as the oxygen pressure exceeds 50 mTorr. The structural information obtained from x-ray diffraction patterns indicates broadening of peak width with increasing laser fluence as well as decreasing substrate temperature. For the film deposited at a lower substrate temperature, a strong (002) texture was observed.


1991 ◽  
Vol 235 ◽  
Author(s):  
Gary A. Smith ◽  
Li-Chyong Chen ◽  
Mei-Chen Chuang

ABSTRACTSystematic experiments have been carried out to characterize the yttria containing zirconia thin films on sapphire substrates by 248nm KrF excimer laser ablation. The deposition rate as a function of laser fluence and O2 pressure at room temperature was measured with a quartz crystal microbalance. The results show different threshold fluences for deposition in vacuum vs. oxygen. While the deposition rate increases with increasing fluence at a given oxygen pressure, the rate eventually saturates at a higher laser fluence. At a given fluence, the oxygen pressure dependence of the deposition rate shows a radical reduction when the O2 pressure increases from 10 mTorr to 1 Torr. Rutherford backscattering spectrometry (RBS) and x-ray photoelectron spectroscopy were used to obtain stoichiometric information. A very strong pressure dependence of the O/Zr ratio was observed. While the trend of increasing O/Zr and Zr/Y ratio with increasing O2 pressure is apparent, the correlations between O/Zr as well as Zr/Y ratio and other processing conditions are less obvious. RBS results indicate an increasing roughness at the interface between the ZrO2 film and the sapphire substrate as the oxygen pressure exceeds 50 mTorr. The structural information obtained from x-ray diffraction patterns indicates broadening of peak width with increasing laser fluence as well as decreasing substrate temperature. For the film deposited at a lower substrate temperature, a strong (002) texture was observed.


2007 ◽  
Author(s):  
F. Sanaa^ ◽  
M. Gharbia ◽  
Mourad Telmini ◽  
Najeh Thabet Mliki ◽  
Ezeddine Sediki

2016 ◽  
Vol 675-676 ◽  
pp. 281-284
Author(s):  
Chatpawee Hom-On ◽  
Mati Horprathum ◽  
Pitak Eiamchai ◽  
Sakson Limwichean ◽  
Viyapol Patthanasetakul ◽  
...  

Aluminum oxide films were grown on (100) silicon wafers and glass substrates by pulsed dc reactive magnetron sputtering deposition. In this experiment, substrate temperatures were varied from room temperature to 500°C. Grazing-incidence X-ray diffraction (GIXRD) analysis revealed that the resulting films have amorphous structures. Field-emission scanning electron microscope (FESEM) was used to characterize the morphology of the films. The films’ optical properties were determined by UV-Vis spectroscopy. The results demonstrated that the deposition rate, the surface roughness and the transmittance spectra of the aluminum oxide films were strongly influenced by the substrate temperature. The deposition rate and the surface roughness of the films were higher at higher substrate temperatures. In the range between 100°C and 200°C, the transmittance spectra were found to be lower than those of the films deposited at other substrate temperatures. This was due to the sub-aluminum oxide condition in the films. The dependence of films’ optical properties on the substrate temperature might result from the change in chemical compositions during the sputtering process.


2006 ◽  
Vol 510-511 ◽  
pp. 674-677 ◽  
Author(s):  
Chong Mu Lee ◽  
Kyung Ha Kim ◽  
Jong Min Lim

Since the hexavalent chromium used in chromium electroplating was found to cause cancer in human body, alternative deposition techniques have been widely investigated. Sputter deposition of chromium (Cr) as a deposition technique for replacing electroplating was studied. Effects of RF-power, substrate temperature on the deposition rate, corrosion-resistance, hardness and adhesion strength were investigated. X-ray diffraction (XRD) analysis was performed to determine the structure and the compositions of the films. The hardnesses of the films were measured by using a nanoindenter. The microstructures of the films were observed using scanning electron microscopy. The deposition rate and hardness of the sputter-deposited Cr film tend to increase with the increasing RF-power and substrate temperature of the sputtering process. Both the hardness and adhesion strength of the sputter-deposited chromium film was found to be higher than those of the electroplated chromium film.


2000 ◽  
Vol 609 ◽  
Author(s):  
W.M.M. Kessels ◽  
A.H.M. Smets ◽  
J.P.M. Hoefnagels ◽  
M.G.H. Boogaarts ◽  
D.C. Schram ◽  
...  

ABSTRACTFrom investigations on the SiH3 and SiH radical density and the surface reaction probability in a remote Ar-H2-SiH4 plasma, it is unambiguously demonstrated that the a-Si:H film quality improves significantly with increasing contribution of SiH3 and decreasing contribution of very reactive (poly)silane radicals. Device quality a-Si:H is obtained at deposition rates up to 100 Å/s for conditions where film growth is governed by SiH3 (contribution ∼90%) and where SiH has only a minor contribution (∼2%). Furthermore, for SiH3 dominated film growth the effect of the deposition rate on the a-Si:H film properties with respect to the substrate temperature is discussed.


Sign in / Sign up

Export Citation Format

Share Document