共查询到20条相似文献,搜索用时 0 毫秒
1.
Silicon - In this work, we emphasis on the Bismuth induced crystallization of hydrogenated amorphous silicon (a-Si) thin films. 50 nm of bismuth thin films are deposited by vapor... 相似文献
2.
CeO_2纳米薄膜的制备 总被引:3,自引:0,他引:3
以 Ce(NO3) 3· 6H2 O为前驱物 ,加入火棉胶作为粘度调节剂 ,采用 sol-gel提拉法制备了均匀透明的 Ce O2 纳米薄膜 ,对其性能进行了研究 ,并用光声光谱确定了 Ce O2 纳米薄膜的透明区间 相似文献
3.
Spectral and Morphological Studies of Nanocrystalline Silicon Thin Films Synthesized by PECVD for Solar Cells 总被引:2,自引:0,他引:2
P. M. Anbarasan P. Senthilkumar S. Manimegalai M. Geetha K. Vasudevan V. Ravi D. Deivasagayam S. Moorthy Babu V. Aroulmoji 《SILICON》2010,2(1):7-17
In this work, a series of nanocrystalline silicon films were studied with different microstructural tools to elucidate the film microstructure at different stages of growth. Thin Si films, with a series of multilayers, were deposited by radio frequency glow discharge using Plasma Enhanced Chemical Vapour Deposition (PECVD) in silane gas (SiH4) highly diluted by hydrogen. Different nanostructured films were prepared by systematically varying gas flow ratios (R = 1/1, 1/5, 1/7.5, 1/10, 1/15, 1/20) for films having different thicknesses. By changing the structure of the material, going from pure amorphous to nanocrystalline silicon, it is possible to obtain a variation in optical gap using the same material. In these structures, layers with different individual optical gaps are stacked together in order to cover as much of the solar spectrum as possible. The nanostructures of the silicon thin films were studied using FTIR, RS, PL, XRD, AFM, SEM, TEM and HRTEM. The results were correlated for conglomerate surface, grain surface. Some theoretical calculations were used for designing the overall stack geometry and for interpretation of characterization. These agree well with experimental observation. 相似文献
4.
Silicon - Hydrogenated silicon carbonitride thin films have been deposited on silicon substrates in a plasma enhanced chemical vapor deposition (PECVD) system using hexamethyldisilazane (HMDSN:... 相似文献
5.
Marat Khafizov In‐Wook Park Aleksandr Chernatynskiy Lingfeng He Jianliang Lin John J. Moore David Swank Thomas Lillo Simon R. Phillpot Anter El‐Azab David H. Hurley 《Journal of the American Ceramic Society》2014,97(2):562-569
The thermal conductivity of nanocrystalline ceria films grown by unbalanced magnetron sputtering is determined as a function of temperature using laser‐based modulated thermoreflectance. The films exhibit significantly reduced conductivity compared with stoichiometric bulk CeO2. A variety of microstructure imaging techniques including X‐ray diffraction, scanning and transmission electron microscopy, X‐ray photoelectron analysis, and electron energy loss spectroscopy indicate that the thermal conductivity is influenced by grain boundaries, dislocations, and oxygen vacancies. The temperature dependence of the thermal conductivity is analyzed using an analytical solution of the Boltzmann transport equation. The conclusion of this study is that oxygen vacancies pose a smaller impediment to thermal transport when they segregate along grain boundaries. 相似文献
6.
Igor Kosacki Vladimir Petrovsky Harlan U. Anderson Philippe Colomban 《Journal of the American Ceramic Society》2002,85(11):2646-2650
The results of Raman-scattering studies of nanocrystalline CeO2 and ZrO2 :16% Y (YSZ) thin films are presented. The relationship between the lattice disorder and the form of the Raman spectra is discussed and correlated with the microstructure. It is shown that the Raman line shape results from phonon confinement and spatial correlation effects and yields information about the material nonstoichiometry level. 相似文献
7.
Emmanouil Lioudakis Andreas Othonos Ch. B. Lioutas N. Vouroutzis 《Nanoscale research letters》2008,3(1):1-5
We have studied ultrafast carrier dynamics in nanocrystalline silicon films with thickness of a few nanometers where boundary-related
states and quantum confinement play an important role. Transient non-degenerated photoinduced absorption measurements have
been employed to investigate the effects of grain boundaries and quantum confinement on the relaxation dynamics of photogenerated
carriers. An observed long initial rise of the photoinduced absorption for the thicker films agrees well with the existence
of boundary-related states acting as fast traps. With decreasing the thickness of material, the relaxation dynamics become
faster since the density of boundary-related states increases. Furthermore, probing with longer wavelengths we are able to
time-resolve optical paths with faster relaxations. This fact is strongly correlated with probing in different points of the
first Brillouin zone of the band structure of these materials. 相似文献
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Chemical and Structural Evolution of Sol-Gel-Derived Hydroxyapatite Thin Films under Rapid Thermal Processing 总被引:1,自引:0,他引:1
Stephen W. Russell Karen A. Luptak Carlos Tres A. Suchicital Terry L. Alford Vincent B. Pizziconi 《Journal of the American Ceramic Society》1996,79(4):837-842
Chemical and structural evolution of hydroxyapatite thin films produced by sol-gel synthesis is characterized by ion beam analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. Formation of the hydroxyapatite structure began at 500°C; no other phases were observed at higher temperatures. Elimination of residual organics was observed in the form of the disappearance of excess oxygen, hydrogen and carbon. Crystal size increases with increasing anneal temperature; spectroscopy indicates the formation of highly crystalline films. The analytical methods chosen provide insight into subtle chemical and structural changes which occur in films produced by this synthetic route. 相似文献
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A polymeric precursor spin-coating technique is illustrated in which yttrium-stabilized zirconia (YSZ) thin films are produced on Si, Al2 O3 , and NaCl at temperatures less than 350°C. High-resolution transmission electron microscopy (HRTEM) examinations show that the YSZ films are nanocrystalline (grain size of less than 5 nm), fully dense, and have a stabilized cubic fluorite structure. Using the polymeric precursor spin coating method, unsupported nanocrystalline thin films of YSZ with thicknesses ranging from 30 to 1000 nm are prepared by transferring the films from a host substrate to metallic TEM grids with unsupported areas exceeding 1 mm2 . 相似文献
14.
A mixed-phase of amorphous (a-Si:H) and ultra nanocrystalline silicon thin films (ultra nc-Si:H) were grown in a low deposition pressure regime (0.10–0.62 Torr) using a very high frequency (60 MHz) plasma enhanced chemical vapor deposition (VHF PECVD) technique. The deposition rate, stress, hydrogen configuration and morphology varying with the deposition pressure were systematically studied. The maximum deposition rate was found to be 8.3 Å/s at a pressure of 0.47 Torr. The stress of these films decreases from 669.7 MPa to 285 MPa with the increase of deposition pressure from 0.10 to 0.62 Torr. The change in deposition pressure showed the variation of the microstructure and hydrogen bonding configuration of the nc-Si:H films. The ultra small crystallites (size?~?2 nm) were formed in the films which were confirmed by the X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) measurements. An attempt was made to understand their growth by analysis of the bonding environment. 相似文献
15.
为了探寻生长过程中硅膜的自晶化沉积,采用等离子体增强化学气相沉积(PECVD)法沉积了氢化硅薄膜,系统研究了不同沉积阶段所得硅膜微观结构的迁变规律。结果表明,硅膜的显微结构依赖于沉积时间,当沉积时间仅为30min时,所得硅膜的结构为非晶;而当沉积时间延至60min时,硅膜形成微晶颗粒;此后随着沉积时间的增加,晶化程度提高,且非晶区域面积相应减小。另外,硅膜的沉积速率也随沉积时间的增加而增加。在硅膜沉积过程中,随时间不断变化的界面状态可能为其自晶化的主要原因。 相似文献
16.
Electrical Conductivity and Lattice Defects in Nanocrystalline Cerium Oxide Thin Films 总被引:2,自引:0,他引:2
Toshio Suzuki Igor Kosacki Harlan U. Anderson Philippe Colomban 《Journal of the American Ceramic Society》2001,84(9):2007-2014
The results of the electrical conductivity and Raman scattering measurements of CeO2 thin films obtained by a polymeric precursor spin-coating technique are presented. The electrical conductivity has been studied as a function of temperature and oxygen activity and correlated with the grain size. When compared with microcrystalline samples, nanocrystalline materials show enhanced electronic conductivity. The transition from extrinsic to intrinsic type of conductivity has been observed as the grain size decreases to <100 nm, which appears to be related to a decrease in the enthalpy of oxygen vacancy formation in CeO2 . Raman spectroscopy has been used to analyze the crystalline quality as a function of grain size. A direct comparison has been made between the defect concentration calculated from coherence length and nonstoichiometry determined from electrical measurements. 相似文献
17.
Sitthisuntorn Supothina Mark R. de Guire Arthur H. Heuer 《Journal of the American Ceramic Society》2003,86(12):2074-2081
Nanocrystalline films of SnO2 were deposited by liquid flow deposition (LFD), i.e., by flowing aqueous solutions of SnCl4 ·5H2 O and HCl over single-crystalline silicon substrates at 80°C. The substrates were either oxidized and fully hydrolyzed (bare silicon) or oxidized, hydrolyzed, and then coated with siloxy-anchored organic self-assembled monolayers (SAMs). Continuous, adherent films formed on sulfonate- and thioacetate-functionalized SAMs; adherent but sometimes discontinuous films formed on bare silicon and methyl-functionalized SAMs. The films contained equiaxed cassiterite crystals, ∼4–10 nm in size. The film thickness increased linearly with deposition time. The maximum growth rate observed was 85 nm·h−1 on sulfonate SAM, and the maximum film thickness obtained was 1 μm. A new dimensionless parameter, the normalized residence time, τ, was introduced for the purpose of interpreting the influence of solution conditions (i.e., degree of supersaturation, as controlled via pH, and tin concentration) and flow characteristics (flow rate and the configuration of the deposition chamber) on the growth rate in LFD processes. The results were consistent with a particle attachment mechanism for film growth and inconsistent with heterogeneous nucleation on the substrate. 相似文献
18.
采用热丝化学气相沉积法,以Sill4、NH3、N2为反应气源,通过改变氮气流量沉积氮化硅薄膜.通过紫外-可见(UV-VIS)光吸收谱、傅里叶红外透射光谱(FTIR)、X射线衍射谱(XRD)等测试手段对薄膜的光学带隙、键合特性及晶相进行表征与分析.结果表明:薄膜主要表现为Si-N键合结构,当N2流量从20 sccm变化到40 sccm时,热丝能够充分的分解N2,薄膜中N原子过量,其周围的Si和H能充分的与N结合.但由于N2的解离能较高,当N2流量高于40 sccm时,氮气在反应过程中对薄膜内的氮原子反而起到了稀释作用,薄膜的有序程度增大,光学带隙减小,致密性降低.当氮气流量达到150 sccm时,在2θ为69.5°处出现了晶化β-Si3 N4的尖锐衍射峰,其择优取向沿(322)晶向,且Si3 N4晶粒显著增大.因此,氮气流量对薄膜中的氮含量有显著影响,适当的增加氮气流量有利于制备出优质含有小晶粒β-Si3 N4薄膜. 相似文献
19.
Silicon - In the current study, novel deposited SiPcCl2 thin films as organic semiconductor were experimentally investigated. The films were prepared using thermal evaporation technique on... 相似文献
20.
A. Hojabri Z. Kavyani M. Ghoranneviss 《Journal of Inorganic and Organometallic Polymers and Materials》2017,27(1):53-60
The silver (Ag) thin films were deposited on silicon substrates by DC magnetron sputtering method under different substrate temperatures of 100–500?°C. Then the as-deposited films were subjected to annealing treatment. The XRD results revealed that the Ag thin films have a good nanocrystalline structure and a considerable increase in the crystallinity of Ag (111) peak was observed at substrate temperature of 200?°C. The average crystalline size of Ag films varied between 18 and 44 nm which confirms the presence of nanocrystal’s in the films. The AFM and SEM images demonstrated that the grain size and surface roughness of the films are sensitive to substrate temperature during deposition of the films and annealing treatment. The SEM results is in good agreement with the results of XRD and AFM analysis. 相似文献