共查询到17条相似文献,搜索用时 125 毫秒
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不同剂量的N离子被注入到化学气相沉积金刚石膜内,研究了表面结构及场发射特性的变化.Raman谱和x射线光电子能谱分析表明,N离子的注入破坏了金刚石膜表面原有的sp3结构,并在膜内形成大量的sp2 C—C 和sp2 C—N 键.样品的场发射测试显示N离子的注入显著提高了金刚石膜场发射特性,膜的场发射阈值电场从注入前的18 V/μm下降到注入后的4 V/μm.金刚石膜场发射特性的提高归因于N离子注入后膜内sp2 C键含量的增加和体内缺陷带的形成,这些变化能改变膜的表面功函数,提高Feimi能级,降低电子隧穿表面的能量势垒.
关键词:
场致电子发射
N离子注入
金刚石膜
热丝化学气相沉积 相似文献
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采用非对称磁镜场电子回旋共振等离子体分别对沉积过程中掺氮和未掺氮的化学气相沉积金刚石膜进行了刻蚀研究, 结果表明: 掺氮制备的金刚石膜的刻蚀主要集中在晶棱处, 经过4h刻蚀后其表面粗糙度由刻蚀前的4.761 μm下降至3.701 μm, 刻蚀对金刚石膜的表面粗糙度的影响较小; 而未掺氮制备的金刚石膜的刻蚀表现为晶面的均匀刻蚀, 晶粒坍塌,刻蚀4h后其表面粗糙度由刻蚀前的3.061 μm下降至1.083 μm. 刻蚀导致表面粗糙度显著降低. 上述差别的主要原因在于金刚石膜沉积过程中掺氮导致氮缺陷在金刚石晶棱处富集, 晶棱处电子发射加强, 引导离子向晶棱运动并产生刻蚀, 从而加剧晶棱的刻蚀. 而未掺氮金刚石膜,其缺陷相对较少且分布较均匀 ,刻蚀时整体呈现为 (111) 晶面被均匀刻蚀继而晶粒坍塌的现象.
关键词:
掺氮
金刚石膜
刻蚀
非对称磁镜场 相似文献
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利用脉冲高能量密度等离子体法在光学玻璃衬底上、在室温下成功的制备了光滑、致密、均匀的纳米类金刚石膜.工艺研究表明:放电电压和放电距离以及工作气体种类对纳米类金刚石膜的沉积起着关键作用.利用拉曼光谱、扫描电镜以及电子能量损失谱分析薄膜的形态结构表明:薄膜具有典型的类金刚石特征;纳米类金刚石膜的晶粒尺寸小于20nm甚至为非晶态;类金刚石膜中含有一定量的氮原子,随着沉积能量的升高,氮的含量增大.纳米类金刚石膜的薄膜电阻超过109Ω/cm2.对放电溅射过程进行了理论分析,结果与工艺研究的结论吻合. 相似文献
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分别应用郎缪尔双探针和离子灵敏探针对非对称磁镜场电子回旋共振氧等离子体的电子参数、空间分布和离子参数进行了测量,分析了气压对等离子体参数及空间分布的影响。利用该等离子体在优化的气压条件下对化学气相沉积金刚石膜进行了刻蚀,并研究了刻蚀机理。结果表明:电子温度为5~10 eV,离子温度为1 eV左右,而等离子体数密度在1010cm-3数量级。随气压的升高,电子和离子温度降低,而电子数密度先增大后减小。在低气压下等离子体数密度空间分布更均匀,优化的刻蚀气压为0.1 Pa。刻蚀过程中,离子的回旋运动特性得到了加强,有利于平行于金刚石膜表面的刻蚀,有效地保护了金刚石膜的晶界和缺陷。 相似文献
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金刚石集群NV色心的光谱特征及浓度定量分析 总被引:1,自引:0,他引:1
金刚石NV-色心具有优越的光致发光特性,可实现高灵敏度物理量探测。其中,NV-色心的浓度是影响其宏观领域物理量探测灵敏度的重要因素之一。分析了金刚石在NV-色心制备过程中产生的发光缺陷,研究了不同的电子注入剂量与NV-色心浓度的关系。首先,对金刚石进行电子辐照并高温真空退火,制备了NV-色心;然后,利用拉曼光谱仪测试了金刚石在电子辐照前、电子辐照后及退火后三个阶段中的荧光光谱,分析了金刚石在NV-色心制备过程中的光谱特性;最后,对生成的NV-色心的浓度进行了估算,并探究了不同电子注入剂量对NV-色心浓度的影响规律。结果表明,金刚石经电子注入后生成了524.7,541.1,578和648.1 nm发光中心。其中,HPHT合成金刚石经电子注入后普遍存在524.7 nm中心。电子注入后的金刚石经高温(≥800 ℃)真空(≥10-7 Pa)退火后,空位自由移动,不稳定的缺陷消失,当空位靠近氮原子时被束缚而形成氮空位色心。对于氮含量100 ppm的金刚石,当电子注入产生的空位含量小于120 ppm(2.1×1019 cm-3)时,NV-色心浓度与电子注入生成空位的含量的关系符合Boltzmann分布。该研究为利用氮含量100 ppm的金刚石实现定量NV-色心浓度的制备提供了参考依据,为NV-色心在宏观物理量精密测量的应用奠定了基础。 相似文献
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The globe-like diamond microcrystalline-aggregates were fabricated by microwave plasma chemical vapor deposition (MPCVD) method. The ceramic with a Ti mental layer was used as substrate. The fabricated diamond was evaluated by Raman scattering spectroscopy, X-ray diffraction spectrum (XRD), and scanning electron microscope (SEM). The field emission properties were tested by using a diode structure in a vacuum. A phosphor-coated indium tin oxide (ITO) anode was used for observing and characterizing the field emission. It was found that the globe-like diamond microcrystalline-aggregates exhibited good electron emission properties. The turn-on field was only 0.55 V/μm, and emission current density as high as 11 mA/cm2 was obtained under an applied field of 2.9 V/μm for the first operation. The growth mechanism and field emission properties of the globe-like diamond microcrystalline-aggregates are discussed relating to microstructure and electrical conductivity. 相似文献
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Yukihiko Okumura Kouichi Kanayama Masaya Tabaru Satoshi Kawabata 《Proceedings of the Combustion Institute》2007,31(2):1831-1838
The purpose of this research is to elucidate the electrical characteristics of a diamond film synthesized by combustion flame and synthesize a diamond film suitable for application in electronic devices. When the film contains amorphous carbon, the dielectric loss increases, i.e., the electrical characteristics of the diamond film are degraded. We employed three methods to decrease the amorphous carbon in the diamond film—the detection of the optimal equivalence ratio, addition of hydrogen into synthesizing gas, and heat treatment (annealing) of the diamond film. All these methods can decrease the amount of amorphous carbon effectively, thus systematically changing the factors influencing the optimal synthesis for improving the electric characteristics of the film. We have successfully developed a method for preparing a high-quality diamond film with excellent electrical characteristics that has no dielectric loss in the wide frequency range (102–108 Hz). 相似文献
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Xinchun ChenZhijian Peng Xiang YuZhiqiang Fu Wen YueChengbiao Wang 《Applied Surface Science》2011,257(8):3180-3186
In order to smooth the rough surface and further improve the wear-resistance of coarse chemical vapor deposition diamond films, diamond/tetrahedral amorphous carbon composite films were synthesized by a two-step preparation technique including hot-filament chemical vapor deposition for polycrystalline diamond (PCD) and subsequent filtered cathodic vacuum arc growth for tetrahedral amorphous carbon (ta-C). The microstructure and tribological performance of the composite films were investigated by means of various characterization techniques. The results indicated that the composite films consisted of a thick well-grained diamond base layer with a thickness up to 150 μm and a thin covering ta-C layer with a thickness of about 0.3 μm, and sp3-C fraction up to 73.93%. Deposition of a smooth ta-C film on coarse polycrystalline diamond films was proved to be an effective tool to lower the surface roughness of the polycrystalline diamond film. The wear-resistance of the diamond film was also enhanced by the self-lubricating effect of the covering ta-C film due to graphitic phase transformation. Under dry pin-on-disk wear test against Si3N4 ball, the friction coefficients of the composite films were much lower than that of the single PCD film. An extremely low friction coefficient (∼0.05) was achieved for the PCD/ta-C composite film. Moreover, the addition of Ti interlayer between the ta-C and the PCD layers can further reduce the surface roughness of the composite film. The main wear mechanism of the composite films was abrasive wear. 相似文献
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采用微波等离子体化学气相沉积(MW-PCVD)和直流热阴极辉光放电等离子体化学气相沉积(DC-PCVD)两种方法相结合,制备出一种吸收辐射的复合金刚石膜,它对宽光谱范围的光辐射具有99%—99.2%的吸收率,同时具有较低的反射率和透过率.随着黑色吸收辐射金刚石层厚度的增加,复合金刚石膜的热导率将小幅度降低,但黑色金刚石膜层厚度小于15 μm时,复合金刚石膜的热导率都在16 W·cm-1·K-1以上,这满足吸收辐射复合金刚石膜的高导热需求.用热阴极DC-PCVD方
关键词:
吸收辐射
光学材料
金刚石
热导率 相似文献
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从理论上推导了材料中空洞分布函数,阐明两种材料,Fe和Ta样品,受不同飞片速度冲击后,其空洞分布的相似性。从文献[5]中又发现,脆性材料的裂纹分布也具有同样的相似性,这说明理论分布函数可能具有普遍性。最后提出了这种性质的广阔应用前景。 相似文献
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用化学气相沉积方法制备了金刚石薄膜.在制备过程中,通过间歇式关闭甲烷气体,强化了氢对sp2杂化碳原子的刻蚀.用拉曼光谱和金相显微镜对薄膜进行了分析表征.结果表明,氢对sp2杂化碳原子的强化刻蚀并未影响金刚石薄膜的品质和微观结构.这一结论说明,在金刚石薄膜中,sp2杂化碳原子主要存在于金刚石晶粒表面和晶界碳原子之间,而不是以石墨或无定形碳颗粒为主要存在方式.
关键词:
化学气相沉积
金刚石薄膜
拉曼光谱
强化刻蚀 相似文献