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1.
Hydrogenated amorphous carbon nitride (a-CN:H) thin films were deposited by hot-wire chemical vapor deposition (HWCVD) using the gas mixture of CH4, NH3 and H2 precursor gases. The structural and electronic environments studies of H2 diluted a-CN:H films were carried out by Raman spectroscopy and X-ray photoelectron spectroscopy. The nitrogen content increases while the total carbon contents decreases with increase in H2 flow rate from 0 sccm to 20 sccm in the a-CN:H films. Moreover, the detail analysis of the carbon core orbital, valence band and hole states of a-CN:H were discussed with different H2 flow rate. 相似文献
2.
Silicon rich silicon oxide films have been deposited by plasma enhanced chemical vapour deposition using a gas mixture of silane, carbon-di-oxide and hydrogen. Silicon nanocrystals formations in the as deposited silicon rich silicon oxide films have been detected by high resolution transmission electron microscopy, scanning electron microscopy, Raman scattering and X-ray diffraction studies. Structural changes under different deposition condition have been studied by Fourier transform infrared spectroscopy. The oxygen and hydrogen bonding configurations have been obtained from Fourier transform infrared spectroscopy. Room temperature photoluminescence spectra have been observed for the as deposited films. The structural properties together with photoluminescence spectra allowed us to gain insight about the Si nanocrystal formation. 相似文献
3.
Bibhu P. Swain Bhabani S. Swain Seung M. Yang Nong M. Hwang 《Applied Surface Science》2009,255(11):6033-6037
Nanocrystalline silicon (nc-Si) films were deposited by hot wire chemical vapor deposition with applying positive or negative filament biases. These films were characterized by Raman spectroscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. Plasmon loss of the Si(2p) band region was shifted to higher energy due to dielectric changes with applied filament biases from negative to positive voltage. A semi-quantitative study of the valence band structure was employed to analyze the bias effect of the valance band in nc-Si networks. Nc-Si with a positive filament bias shows better microstructural properties than those with a negative bias and without biasing nc-Si films. 相似文献
4.
Su Kong Chong Boon Tong Goh Yuen-Yee Wong Hong-Quan Nguyen Hien Do Ishaq Ahmad Zarina Aspanut Muhamad Rasat Muhamad Chang Fu Dee Saadah Abdul Rahman 《Journal of luminescence》2012,132(6):1345-1352
High density of silicon nanowires (SiNWs) were synthesized by a hot-wire assisted plasma enhanced chemical vapor deposition technique. The structural and optical properties of the as-grown SiNWs prepared at different rf power of 40 and 80 W were analyzed in this study. The SiNWs prepared at rf power of 40 W exhibited highly crystalline structure with a high crystal volume fraction, XC of ~82% and are surrounded by a thin layer of SiOx. The NWs show high absorption in the high energy region (E>1.8 eV) and strong photoluminescence at 1.73 to 2.05 eV (red–orange region) with a weak shoulder at 1.65 to 1.73 eV (near IR region). An increase in rf power to 80 W reduced the XC to ~65% and led to the formation of nanocrystalline Si structures with a crystallite size of <4 nm within the SiNWs. These NWs are covered by a mixture of uncatalyzed amorphous Si layer. The SiNWs prepared at 80 W exhibited a high optical absorption ability above 99% in the broadband range between 220 and ~1500 nm and red emission between 1.65 and 1.95 eV. The interesting light absorption and photoluminescence properties from both SiNWs are discussed in the text. 相似文献
5.
Hoon Young Cho Chan Jin Park 《Physica E: Low-dimensional Systems and Nanostructures》2003,16(3-4):489
Single crystalline Si epilayers were grown on sapphire
substrates through a three-step growth method by rapid thermal chemical vapor deposition (RTCVD). Hydrogenation of the epilayers was performed by the hydrogen-plasma exposure (HPE) in a remote plasma chemical vapor deposition (RPCVD) system, following rapid thermal annealing. It was found that the hydrogenation treatment improves the crystallinity of the Si epilayer as well as the electrical properties of Si epilayers. After hydrogenation, especially, the intensity of the deep level defects which are responsible for the lattice mismatch between Si and the sapphire substrate decreases. Also, dislocations and microtwins are reduced remarkably, improving the crystallinity. In Schottky diodes fabricated on hydrogenation-processed Si epilayers, the leakage current decreases one order of magnitude in comparison to non-hydrogenated samples. It is suggested that these characteristics could be explained by the hydrogen incorporation at defects. 相似文献
6.
《Current Applied Physics》2020,20(1):191-195
We investigated the effect of hydrogen dilution on the Si cluster volume fraction of hydrogenated amorphous films by varying the hydrogen dilution ratio at 0.5 Torr and compared it to that obtained at pure silane discharge at 0.3, 0.4, and 0.5 Torr. The correlation between the plasma emission characteristic, deposition rate, and cluster volume fraction in the hydrogen dilution plasma was described. The cluster volume fractions of films under hydrogen dilution conditions were similar to those of the pure silane but showed a higher deposition rate. The results suggest that under hydrogen dilution conditions, it is possible to maintain a higher deposition rate with a lower cluster incorporation rate. 相似文献
7.
A. Benami G. Santana B.M. Monroy A. Ortiz J.C. Alonso J. Fandio J. Aguilar-Hernndez G. Contreras-Puente 《Physica E: Low-dimensional Systems and Nanostructures》2007,38(1-2):148
The photoluminescence (PL) of silicon nanoclusters embedded in silicon nitride films grown by remote plasma-enhanced chemical vapor deposition at 200 °C, using mixtures of SiCl4/H2/Ar/NH3 is investigated. It was found that the color and the intensity of the PL of the as-grown samples depend on the H2 flow rate, and there is an optimum flow for which a maximum luminescence is obtained. A strong improvement of the PL intensity and change in color was obtained with annealing treatments in the range of 500–1000 °C. The changes in the composition, structure and optical properties of the films, as a function of H2 flow rate and thermal treatments, were studied by means of Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, ellipsometry and ultraviolet–visible transmission measurements. We conclude that the PL can be attributed to quantum confinement effect in silicon nanoclusters embedded in silicon nitride matrix, which is improved when a better passivation of the nanoclusters surface is obtained. 相似文献
8.
The effect of temperature on growth and structure of carbon nanotubes (NTs) using chemical vapor deposition (CVD) has been
investigated. Iron embedded silica was used to grow NTs in large quantity at various temperatures from 600 to 1050 °C with
gas pressure fixed at 0.6 and 760 Torr, respectively. The growth and structure of the NTs are strongly affected by the temperature.
At low gas pressure, the NTs are completely hollow at low temperature and bamboo-like structure at high temperature. While
at high gas pressure, all the NTs are bamboo-like structure regardless of temperature. The diameter of NTs increases significantly
with temperature. At low gas pressure the diameter gets bigger by mainly increasing the number of graphene layers of the wall
of NTs, whereas at high gas pressure the diameter gets bigger by increasing both the number of graphene layers of the wall
and the inner diameter of the NTs. This result indicates that the growth temperature is crucial in synthesizing NTs with different
structures. The findings here are important for realizing controlled growth of NTs for their applications in different fields.
Received: 20 November 2001 / Accepted: 21 November 2001 / Published online: 4 March 2002 相似文献
9.
通过化学气相沉积法在不同衬底上制备了大量的氧化硅纳米线.选用衬底为Si片、带有约100nm厚SiO2氧化层Si片和石英片.利用场发射扫描电子显微镜(SEM)和透射电镜(TEM,配备有能谱仪)对样品的表面形貌、结构和成分进行研究.结果表明:这些纳米线都为非晶态,但在不同衬底上生长的纳米线形貌、尺寸和化学成分不同.讨论了各种衬底对不同特征氧化硅纳米线生长的影响.
关键词:
化学气相沉积
纳米线
纳米颗粒 相似文献
10.
Li Sun Yan-Feng Chen Lei He Chuan-Zheng Ge Tao Yu Ming-Sheng Zhang Nai-Ben Ming De-Sheng Ding Yin-Chuan Chang 《Zeitschrift für Physik B Condensed Matter》1997,102(4):479-482
(001) preferentially oriented PbTiO3 thin films have been grown on (110) NdGaO3 substrates by metalorganic chemical vapor deposition (MOCVD) under reduced pressure at 650°C. Atomic force microscopy (AFM) surface morphology of the as-deposited film showed the evidence of layer-by-layer growth in the MOCVD process. By using a grazing-angle scattering technique, a highly resolved Raman spectrum of the epitaxial PbTiO3thin film on perovskite substrate was first time recorded. Other microstructure of the film, such as the element composition, the c-domain percentage and the epitaxial nature, were investigated by Rutherford backscattering spectrometry (RBS), x-ray θ ? 2θ diffraction patterns and x-ray φ scans, respectively. All measurements indicate that NdGaO3single crystal, which used to be a substrate for the growth of high-Tc superconducting thin films, is also suitable for the growth of high quality PbTiO3 thin film. This indicates the promising use of the NdGaO3 for the integration of ferroelectric thin films and superconducting electrodes. 相似文献
11.
12.
The effect of Al incorporation on the AlGaN growth by metalorganic chemical vapor deposition is investigated. With the increase of trimethylalluminum (TMAl) flux, the crystal quality becomes worse, and the epilayer surface becomes rougher. An interesting phenomenon is that the growth rate of AlGaN decrease with increasing TMAl flux, which is opposite to the AlN growth rate dependence on the TMAl flux. All these effects are attributed to the different properties of Al atoms due to the higher bond strength of Al-N compared with Ga-N, which lead to lower surface mobility and stronger competitive ability of Al atoms during the growth. The enhancement of the surface mobility of Al is especially important for improving the quality of AlGaN. 相似文献
13.
Jihe Lü 《中国光学快报(英文版)》2007,5(7)
Using two-step method InP epilayers were grown on GaAs(100) substrates by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). X-ray diffraction (XRD) and room-temperature (RT) photoluminescence (PL) were employed to characterize the quality of InP epilayer. The best scheme of growing InP/GaAs(100) heterostructures was obtained by optimizing the initial low-temperature (LT) InP growth conditions, investigating the effects of thermal cycle annealing (TCA) and strained layer superlattice (SLS)on InP epilayers. Compared with annealing, 10-periods Ga0.1In0.9P/InP SLS inserted into InP epilayers can improve the quality of epilayers dramatically, by this means, for 2.6-μm-thick heteroepitaxial InP, the full-widths at half-maximum (FWHMs) of XRD ω and ω-2θ scans are 219 and 203 arcsec, respectively, the RT PL spectrum shows the band edge transition of InP, the FWHM is 42 meV. In addition, the successful growth of InP/In0.53Ga0.47As MQWs on GaAs(100) substrates indicates the quality of device demand of InP/GaAs heterostructures. 相似文献
14.
Can Wang Yan-li Wang Wen-Ming Qiao Xiaoyi Liang Li-Cheng Ling 《Applied Surface Science》2010,257(3):932-936
Thiophene was introduced as an additive in detonation-assisted chemical vapor deposition to investigate the effect of sulfur on the growth of carbon nanotubes. The results reveal that sulfur promoted the growth of hollow tubes, instead of bamboo-like carbon nanotubes without sulfur addition. Structural characterization of products indicates that the dynamic reshaping of the catalyst assisted bamboo-like carbon nanotube growth and the bamboo knots preferentially nucleated on the Ni-graphite step edges. It is suggested that sulfur suppressed the bamboo knot growth through blocking the step sites. The findings are important for understanding of nanotube growth mechanism and the role of sulfur often involved in catalytic reactions. 相似文献
15.
结合丝网印刷和过滤阴极真空电弧法、离子束溅射方法,在普通玻璃衬底上制备催化剂图案,采用低温热化学气相沉积法(CVD)生长碳纳米管/纤维(CNTs)薄膜.研究了不同种类催化剂对CNTs薄膜生长及其场发射的影响.结果表明,在a-C:Co,Ni-Cu和Cu三种催化剂上没有获得明显的CNTs,在外加电场小于4.4V/μm时没有观察到场发射;而在Ni-Fe及Ni-Cr两种催化剂上获得了大量的CNTs,并且表现出良好的场发射性能,开启电场为2.5V/μm,这种热CVD有简单、低温等优点,在CNTs场发射显示器的阴极制备中有潜在的应用价值. 相似文献
16.
ZnO nanowire arrays have been successfully synthesized on transparent quartz glass substrate by chemical vapor deposition technique. Our work demonstrates the critical role of the growth temperature and the buffer layer on the effective control of the morphology of ZnO nanowires. A proper growth temperature and the thicker buffer layer could promise the good alignment and high density of the nanowires. The room-temperature photoluminescence spectrum shows that the buffer layer has also great effects on optical properties of ZnO nanowire arrays. The integrated intensity ratio [IUV/IVisible band] of the ZnO UV emission peak to visible band emission decreases with the increase of the thickness of the buffer layers. The obtained nanowire arrays have transmittance of above 50% in the visible region. 相似文献
17.
Poulami Ghosh Ashwini Kumar Sharma 《Applied Physics A: Materials Science & Processing》2014,116(4):1877-1884
We report on the growth of highly c-axis-oriented ZnO nanostructures by pulsed laser deposition technique without using any catalyst. The full-width-at-half-maximum of (002) peak decreased with an increase in substrate temperature. However, a dip at 150 °C is attributed to the contribution from both the small- and large-size particles. FE-SEM images show that the increase in substrate temperature results in the formation of larger particles. Photoluminescence emission is observed both from near band edge as well as defect-related states for all the nanostructures. The presence of E 2(low) and E 2(high) Raman mode intensity and respective increase in the intensity with substrate temperature indicates better crystallinity. Both PL and Raman spectra indicate that A 1(LO) mode may arise due to the defect related to interstitial zinc. 相似文献
18.
Experiments conducted in an industrial tubular low pressure chemical vapor deposition (LPCVD) reactor have demonstrated the reproducibility and spatial uniformity of silicon nanodots (NDs) area density and mean radius. The wafer to wafer uniformity was satisfactory (density and radius standard deviations <10%) for the whole conditions tested except for low silane flow rates, high silane partial pressures and short run durations (<20 s). Original synthesis conditions have then been searched to reach both excellent wafer to wafer uniformities along the industrial load of wafers and high NDs densities. From previous results, it was deduced that the key was to markedly increase run duration in decreasing temperature and in increasing silane pressure. At 773 K, run durations as long as 180 and 240 s have thus allowed to reach NDs densities respectively equal to 9 × 1011 and 6.5 × 1011 NDs/cm2 for the two highest silane pressures tested in the range 60-150 Pa. 相似文献
19.
R. Saravana Kumar P. Sudhagar R. Sathyamoorthy P. Matheswaran Yong Soo Kang 《Superlattices and Microstructures》2009
In this work, spindle/flower-like zinc oxide (ZnO) nanostructured arrays have been directly grown on glass substrates using triethanolamine (TEA) as a complexing agent by chemical bath deposition (CBD). Control over the morphology of ZnO nanocrystallites was achieved by varying the concentration of the complexing agent in the bath solution. ZnO crystallites exhibited a hexagonal wurtzite structure with preferential orientation along the c-axis. The morphology of the ZnO crystallites with star or needle-like spindles was altered to flower like nanostructures by adjusting the complexing agent concentration. Compared to as-deposited films, films sintered at 300 °C exhibited a sharp UV emission due to a decrease in the defect density. A possible growth mechanism for obtaining ZnO nanoflower arrays without a seed layer on glass substrates has been discussed. 相似文献
20.
Habib Hamidinezhad Yussof WahabZulkafli Othaman Abd Khamim Ismail 《Applied Surface Science》2011,257(21):9188-9192
Silicon nanowires (SiNWs) were synthesized from pure silane precursor gas and Au nanoparticles catalyst at below Au-Si eutectic temperature. The SiNWs were grown onto Si (1 1 1) substrates using very high frequency plasma enhanced chemical vapor deposition via a vapor-solid-solid mechanism at temperatures ranging from 363 to 230 °C. The morphology of the synthesized SiNWs was characterized by means of field emission scanning electron microscope equipped with energy dispersive X-ray, high resolution transmission electron microscopy, X-ray diffraction technique and Raman spectroscope. Results demonstrated that the SiNWs can be grown at the temperature as low as 250 °C. In addition, it was revealed that the grown wires were silicon-crystallized. 相似文献