共查询到20条相似文献,搜索用时 78 毫秒
1.
利用热丝化学气相沉积法研究了氮气浓度对金刚石薄膜成核和生长的影响.实验发现氮气的 加入对金刚石成核密度影响不大,但促进了已形成的金刚石核的长大.适量的氮气不仅使金 刚石生长速率得到很大的提高,而且稳定了金刚石薄膜(100)面的生长,使金刚石薄膜具有 更好的(100)织构.利用原位光发射谱对衬底附近的化学基团进行了研究.研究表明,氮气的 引入使得金刚石生长的气相化学和表面化学性质发生了很大变化.含氮基团的萃取作用提高 了金刚石表面氢原子的脱附速率,从而提高了金刚石膜的生长速率.而含氮基团的选择吸附 使金刚石
关键词:
氮气
金刚石薄膜
织构
原位光发射谱 相似文献
2.
3.
4.
螺旋线慢波组件的散热性能是影响行波管输出功率、工作稳定性及可靠性的重要因素. 金刚石材料具有极高的导热性能,将金刚石材料应用于螺旋线慢波组件的制备,可以在一定程度上改善组件散热性能. 本文计算模拟分析了沉积金刚石薄膜的夹持杆、沉积金刚石薄膜的螺旋线以及金刚石夹持杆对慢波组件散热性能的影响. 结合实验和模拟对比研究,使计算机仿真与实验测试紧密关联,提高了计算机模拟研究准确性,为金刚石材料在慢波组件中的应用提供了重要的参考依据.
关键词:
螺旋线行波管
慢波组件
散热性能
金刚石 相似文献
5.
金刚石晶体不仅具有极佳的光学性质,同时也拥有极高的热导率和低的热膨胀系数,这使得金刚石激光器成为实现不受热影响高功率激光输出的重要路径。但随着激光功率的进一步提升,金刚石拉曼激光器中仍然存在不可忽视的热效应等问题,这对金刚石激光器性能提升提出了挑战。针对高功率运转情况下金刚石拉曼激光器的热效应进行了理论研究,根据热传导方程并采用有限元分析方法,模拟了金刚石温度、热应力以及热形变分布,分析了泵浦参数、晶体参数对金刚石温度、热应力、热形变的影响。此外,基于石墨片横向导热特性,设计了一种新型的用于金刚石晶体的热沉结构。与传统单一铜片散热方式相比,在泵浦功率800 W、束腰半径40μm条件下,金刚石中心温度下降了10.16 K,下表面平均应力降低了19.857 MPa,端面平均形变量减小了0.055μm。数值模拟结果表明,该方法对缓解金刚石激光的热效应,实现金刚石拉曼激光器输出功率的进一步提升和高光束质量激光输出具有重要指导意义。 相似文献
6.
高压合成金刚石聚晶的耐磨性与其所含金刚石粒度的关系 总被引:3,自引:0,他引:3
本文通过原料金刚石聚晶(PCD)耐磨性影响的实验研究,发现金刚石粒度的变化对PCD耐磨性有显著影响。同时,作者在对PCD的微观形貌的观察和分析的基础上,提出细粒金刚石PCD耐磨性提高的主要原因是其自身致密度的增加。 相似文献
7.
在对前人有关聚晶金刚石超高压烧结机理的综合分析与评价的基础上,通过对金刚石与不同组分的钴熔体相互作用规律,及金刚石从钴熔体中的结晶热力学与动力学的理论研究,提出了石墨优先金刚石“溶解”和金刚石石墨化“溶解”的观点,阐明了钴熔体的性质对金刚石(石墨)的浸润扩散溶解过程,以及金刚石再结晶析出过程的影响,认为在金刚石-钴烧结系统中存在三种主要烧结机构:颗粒重排,溶解-析出和聚晶固架形成机构。不同温度条件下不同碳含量钴熔体在烧结过程中,对于促进金刚石表面石墨化,进一步引起颗粒重排,实现sp3结构碳原子在金刚石颗粒间的有效迁移传递以及D-D直接结合等方面起到了十分重要的作用。根据上述金刚石超高压液相烧结理论的基本观点,可较合理地解释聚晶金刚石复合体(PDC)在超高压烧结过程中观察到的一些基本现象和实验事实。 相似文献
8.
9.
10.
11.
Manisree Majumder 《Journal of luminescence》2010,130(8):1497-1503
Nanostructured cadmium sulfide (CdS) thin films have been prepared by chemical bath deposition (CBD) method and after post deposition annealing of the thin films at different temperatures, photoluminescence (PL) property has been studied. The effects of various photoexcitation wavelengths on the PL behaviour of different annealed films of CdS were studied by recording the PL spectra. The intensity of PL, the profile of the PL spectra and the effects of photoexcitation wavelength depend drastically on the temperature of the post deposition annealing of the thin films. The XRD patterns of the films show the presence of both the hexagonal and cubic phases (mixed phases). The emission peak arises from the surface defects of the CdS nanocrystalline thin films. Significant modification in the surface morphology of the CdS films upon annealing has been observed from the FESEM images. The morphology of the thin films is expected to influence the PL behaviour of the CdS thin films. The quantum size effect and size dependant PL have been observed. 相似文献
12.
采用电子束镀膜方法在Si基底上制备了Sc膜,利用XRD,SEM分析了不同镀膜工艺条件下制备的Sc膜的形貌和结构。结果表明:基底温度在350~550 ℃时,薄膜主要由单质Sc组成,而且随着基底温度的升高,膜的颗粒尺寸增大,膜也变得更加致密;基底温度提高至650 ℃时,膜全部由ScSi化合物组成,膜变成颗粒状结构。沉积速率对低温时Sc膜的形貌与结构的影响不明显,颗粒尺寸随沉积速率的增大而增大,但物相结构基本没有发生变化;而在高温650 ℃时,沉积速率对膜的形貌与结构产生了很大的影响,随着沉积速率的增大,膜表面出现了大量微裂纹,而且较低的沉积速率有利于获得衍射峰单一的膜,增大沉积速率将会导致衍射峰数量明显增加。 相似文献
13.
14.
15.
通过直流磁控反应溅射制备了氮化铝(AlN)薄膜,研究了沉积条件与氮化镓(GaN)缓冲层对薄膜质量的影响。利用X-射线衍射仪(XRD)和扫描电镜(SEM)表征了AlN薄膜的晶体结构和表面形貌。XRD研究结果表明,低工作压强、短靶距和适当的氮气偏压有利于(002)择优取向的AlN薄膜沉积。随着沉积时间的增加,沉积在50 nm厚的GaN缓冲层上的AlN薄膜的(002)面的衍射峰的半高宽急剧减小,而沉积在1μm厚的GaN薄膜上的AlN薄膜的(002)面的衍射峰的半高宽几乎不变。SEM测试结果表明:在沉积的初期,沉积在1μm厚的GaN薄膜上的AlN薄膜的(002)面的晶粒大小分布比沉积在50 nm厚的GaN缓冲层上的AlN薄膜的均匀,而随着沉积时间的增加,它们的晶粒大小分布几乎趋向一致。 相似文献
16.
17.
Microcrystalline boron-doped diamond (BDD) films are synthesized on the silicon substrate by the hot-filament chemical vapor deposition method under the gas mixture of hydrogen and methane in the presence of boron carbide (B4C) placed in front of filaments. The observed results of scanning electron microscopy, Raman spectroscopy and X-ray diffraction show the morphologies. Microstructures for various deposition pressures of as-grown diamond films are found to be dependent on the change of deposition pressure. These results reveal that with the increase of deposition pressure, resistivity decreases and increase in the grain size is noted in the presence of B4C. Resistivity shows a sudden fall of about three orders of magnitude by the addition of boron in the diamond films. This is due to the crystal integrity induced by B-atoms in the structure of diamond in the presence of B4C. These results are also significant for the conventional applications of BDD materials. The effects of deposition pressure on the overall films morphology and the doping level dependence of the diamond films have also been discussed. 相似文献
18.
《Physics letters. A》1997,235(3):267-270
The growth of Cu films by pulsed laser deposition (PLD) is studied with molecular dynamics simulations. We focus on examining the effects of high momentary deposition rate and energetic particle impact in the PLD process. Simulations show that these two factors can promote surface atomic mobility and lead to 2D smooth growth of films at lower substrate temperature. These features are consistent with experiments. 相似文献
19.
以GaP为靶材、Ar为工作气体,采用射频磁控溅射法制备了厚层GaP膜.对沉积过程中的辉光放电等离子体进行了发射光谱诊断,发现只有ArⅠ发射谱线.研究了工艺参数对发射谱线强度的影响规律,并在此基础上通过同时改变射频功率、Ar气流量及工作气压,使ArⅠ发射谱线强度保持相同.发现通过增大射频功率、减小工作气压而保持ArⅠ发射谱线强度不变可以提高GaP膜的沉积速率,并使GaP膜的沉积工艺参数得到优化.在优化后的工艺参数下制备出了符合化学计量比、红外透过性能好的厚层GaP膜.
关键词:
GaP薄膜
射频磁控溅射
等离子体发射光谱
红外透射 相似文献
20.
W.Y. Zhang H. Shima M. Takenaka K. Masuda T. Nagahama 《Journal of magnetism and magnetic materials》2010,322(8):900-908
In this study, the deposition pressure dependence of the compositional ratio, magnetic domain structure, and perpendicular magnetic anisotropy (PMA) of B-containing PrFe- and PrCo-based films, which are rare-earth-transition-metal (RE-TM) films, was investigated. PrFe- and PrCo-based films were fabricated by magnetron sputtering. The film compositions were controlled in a wide range by varying the deposition pressure. On the basis of experimental results, the residual stress of the films was considered to be the possible origin of their PMA. The films showed strong magneto-optical effects over the entire wavelength range of 300-750 nm. Because of the excellent magnetic and magneto-optical (MO) properties of the films, they have high potential for MO applications at wavelengths of red and blue lasers. 相似文献