共查询到18条相似文献,搜索用时 125 毫秒
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Si衬底用化学方法清洗后,表面大约残余1.0 nm厚SiO2薄膜.利用原子力显微镜(AFM)和反射高能电子衍射(RHEED)来研究温度和Ge蒸发厚度对在SiO2薄膜表面生长的Ge量子点的影响.实验结果表明,当衬底温度超过500 ℃时,SiO2开始与Ge原子发生化学反应,并形成与Si(111)表面直接外延的Ge量子点.在650 ℃时,只有Ge的厚度达到0.5nm时,Ge量子点才开始形成. 相似文献
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一种新型Si电子束蒸发器的研制及其应用研究 总被引:1,自引:0,他引:1
我们成功地设计出一种新型的Si电子束蒸发器,并将它应用于Ge/Si(111)量子点的生长.由于采用悬臂式设计,它完全克服了高压短路的问题.电子束蒸发器的性能试验表明,稳定输出功率可以控制输出稳定的Si束流.应用这种电子束蒸发器可以在700 ℃,成功沉积出平整的单晶Si薄膜.进一步的试验表明,在这种缓冲层表面可以自组装生长出Ge量子点. 相似文献
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采用射频磁控溅射方法以石英玻璃为衬底分别沉积制备出了Ge/SiO2和Ge/ZnO/SiO2薄膜。X射线衍射表明薄膜展示了明显的ZnO衍射峰和较弱的Ge衍射峰;傅里叶变换红外光谱曲线证明薄膜均具有各自的特征吸收峰;扫描电镜结果显示薄膜为颗粒状团簇结构,并且加入ZnO中间层可以有效的改善Ge层的质量。同时,对所得薄膜材料的电流-电压性能进行了研究,结果发现,Ge/SiO2薄膜的I-V曲线拟合后为斜线,相当于电阻;ZnO/SiO2薄膜为直线,可以认为是绝缘体;Ge/ZnO/SiO2薄膜在-10~10V之间电流电压呈线性关系,其电阻比Ge/SiO2薄膜小,当电压值超过15V之后,电流急剧增加而迅速使薄膜击穿,薄膜导通。 相似文献
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利用扫描隧道显微镜 (STM) ,研究了Si(111)表面的 2× 2、c2× 4、9× 9和 11× 11等各种亚稳态结构。与已经发表的研究结果相比 :2× 2和c2× 4重构区域规则且面积更大 ,原子分辨的图像清晰稳定 ;在不同亚稳态之间的畴界处 ,发现存在2种不同的环形结构。从原子密度和能量两方面 ,对各种亚稳态重构的形成机制进行了讨论 相似文献
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用超高真空扫描隧道显微镜(UHV-STM)研究了金属富勒烯分子Gd@C82在Si(111)7×7重构表面的吸附特性和电学特性.STM形貌像显示Gd@C82分子和Si基底之间相互作用较强,Gd@C82分子吸附在Si基底的三种特定的位置上,其中在Si(111)7×7单胞内三个顶戴原子间的吸附位最稳定.扫描隧道谱(STS)的测量显示Gd@C82分子呈现半导体特性.分子表面局域电子态密度(LDOS)在Gd附近受到Gd与碳笼间电子转移的影响,发生显著变化. 相似文献
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采用脉冲激光沉积方法在Si(111)基片上制备了Mg2Si薄膜。研究了激光能量密度、退火气氛及压强、退火温度、退火时间等工艺条件对Mg2Si薄膜生长的影响。用X射线衍射仪分析了Mg2Si薄膜的物相,用原子力显微镜、高分辨场发射扫描电镜表征了薄膜的形貌。实验结果表明:在激光能量密度为2.36 J/cm2,Si(111)基片上室温、真空(真空度10-6Pa)条件下沉积,在Ar气压强为10 Pa,500℃,30 min条件下原位退火得到了纯相、结构均匀、表面平整、厚度约为900 nm的Mg2Si多晶薄膜。 相似文献
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利用超高真空扫描隧道显微镜(UHV STM)研究了室温条件下沉积在Si(111)7×7重构表面不同覆盖度的Ag粒子.实验结果表明,低覆盖度时的Ag粒子主要有A、B两种类型,其中A型Ag粒子呈环状结构,最小的A型Ag粒子由3个Ag原子组成;而B型Ag粒子则是由两层Ag原子构成.高覆盖度时Ag粒子的生长过程为层岛混合生长(Stranski-Krastanov)模式.本文还研究了不同蒸发速率对Ag原子成核的影响,发现在高蒸发速率条件下Ag原子在Si(111)7×7重构表面更容易成核. 相似文献
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Si(111)衬底上多层石墨烯薄膜的外延生长 总被引:1,自引:0,他引:1
利用固源分子束外延(SSMBE)技术, 在Si(111)衬底上沉积碳原子外延生长石墨烯薄膜, 通过反射式高能电子衍射(RHEED)、红外吸收谱(FTIR)、拉曼光谱(RAMAN)和X射线吸收精细结构谱(NEXAFS)等手段对不同衬底温度(400、600、700、800℃)生长的薄膜进行结构表征. RAMAN和NEXAFS结果表明: 在800℃下制备的薄膜具有石墨烯的特征, 而 400、600和700℃生长的样品为非晶或多晶碳薄膜. RHEED和FTIR结果表明, 沉积温度在600℃以下时C原子和衬底Si原子没有成键, 而衬底温度提升到700℃以上, 沉积的C原子会先和衬底Si原子反应形成SiC缓冲层, 且在800℃沉积时缓冲层质量较好. 因此在Si衬底上制备石墨烯薄膜需要较高的衬底温度和高质量的SiC缓冲层. 相似文献
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Use of germanium as a storage medium combined with a high-k dielectric tunneling oxide is of interest for non-volatile memory applications. The device structure consists of a thin HfO2 tunneling oxide with a Ge layer either in the form of continuous layer or discrete nanocrystals and relatively thicker SiO2 layer functioning as a control oxide. In this work, we studied interface properties and formation kinetics in SiO2/Ge/HfO2(Ge) multilayer structure during deposition and annealing. This material structure was fabricated by magnetron sputtering and studied by depth profiling with XPS and by Raman spectroscopy. It was observed that Ge atoms penetrate into HfO2 layer during the deposition and segregate out with annealing. This is related to the low solubility of Ge in HfO2 which is observed in other oxides as well. Therefore, Ge out diffusion might be an advantage in forming well controlled floating gate on top of HfO2. In addition we observed the Ge oxidation at the interfaces, where HfSiOx formation is also detected. 相似文献
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Yoshiaki Nakamura Kenjiro FukudaShogo Amari Masakazu Ichikawa 《Thin solid films》2011,519(24):8512-8515
Ultrahigh density (> 1012 cm−2) Fe3Si nanodots (NDs) are epitaxially grown on Si(111) substrates by codeposition of Fe and Si on the ultrathin SiO2 films with ultrahigh density nanovoids. We used two kinds of methods for epitaxial growth: molecular beam epitaxy (MBE) and solid phase epitaxy. For MBE, low temperature (< 300 °C) growth of the Fe3Si NDs is needed to suppress the interdiffusion between Fe atoms deposited on the surfaces and Si atoms in the substrate. These epitaxial NDs exhibited the ferromagnetism at low temperatures, which were expected in terms of the application to the magnetic memory device materials. 相似文献
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We present the study of formation of Ge-nanoparticles (Ge-NP) in germanosilicate (Ge:SiO2) multilayer (ML) films under thermal treatment. In anticipation of controllable formation of Ge-NP, ML films were prepared by magnetron deposition at room temperature as 20 bi-layer stacks, each bi-layer comprised of a 7 nm thick layer of (Ge + SiO2) (molar ratio: 60:40) succeeded by a 7 nm thick layer of pure SiO2, and then annealed for 1 h, up to Ta = 900 °C. Formation and morphology of Ge-NP were analyzed by combining the information obtained from the grazing incidence small angle X-ray scattering and X-ray diffraction. It was found that precipitation of Ge-NP starts at Ta = 600 °C, while high degree of in-plane confinement and lateral ordering of rather uniform precipitated particles is achieved at Ta = 700-800 °C range. At still higher annealing temperature Ta > 800 °C, volume fraction of precipitated Ge-NP in SiO2 matrix diminishes due to the out-diffusion of Ge atoms from the film, while Ge-NP are no more well confined to (Ge + SiO2) layers. 相似文献
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Multilayer germanosilicate (Ge:SiO2) films have been grown by plasma enhanced chemical vapor deposition. Each Ge:SiO2 layer is separated by a pure SiO2 layer. The samples were heat treated at 900 °C for 15 and 45 min. Transmission electron microscopy investigations show precipitation of particles in the layers of highest Ge concentration. Furthermore there is evidence of diffusion between the layers. This paper focuses mainly on observed growth of Ge particles close to the interface, caused by Ge diffusion from the Ge:SiO2 layer closest to the interface through a pure SiO2 layer and to the interface. The particles grow as spheres in a direction away from the interface. Particles observed after 15 min anneal time are 4 nm in size and are amorphous, while after 45 min anneal time they are 7 nm in size and have a crystalline diamond type Ge structure. 相似文献
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利用扫描隧道显微镜和超高真空实验装置系统进行了Si(10 0 )表面生长Si,Ge的实验研究。分析了所生成表面的形貌、结构等物理性质。研究表明 :Si在Si(10 0 )表面的同质生长可以形成纳米结构薄膜。Ge在Si(10 0 )表面生长形成规则的三维小岛。而在Si/Ge/Si(10 0 )多层膜上生长则形成大小二种三维岛。研究表明大岛具有Ge/Si/Ge的壳层结构 相似文献
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J.Y. Son 《Thin solid films》2009,517(11):3262-3264
A highly a-oriented SrBi2Ta2O9 thin film with a polycrystalline structure was deposited on a preferentially oriented (111) Pt/TiO2/SiO2/Si substrate by eclipse pulsed laser deposition (PLD) method. The SrBi2Ta2O9 thin film exhibited flat and smooth surface with the surface roughness of about 0.5 nm resulting from reducing particulates generated by on-axis PLD. The SrBi2Ta2O9 thin film showed a good ferroelectric property with the high remanent polarization of 12 μC/cm2 and the low coercive electric field of 140 kV/cm. For the highly a-oriented SBT thin film, domain switching and reading were performed by Kelvin probe force microscope (KFM). The KFM data indicate a good ferroelectric property of the highly a-oriented SrBi2Ta2O9 thin film with high KFM signals that reflect ferroelectric polarizations. 相似文献