Fe掺杂氢化非晶碳薄膜制备及其热稳定性能

 以H₂、反式-2-丁烯（T₂B）和二茂铁混合气体为工作气体,用金属有机等离子体增强化学气相沉积法（PECVD）制备了Fe掺杂氢化非晶碳（a-C:H:Fe）薄膜。使用X射线光电子能谱（XPS）对a-C:H:Fe薄膜成分进行了分析。使用台阶仪、场发射扫描电镜（FESEM）、热重分析和紫外可见分光光度计（UV-VIS）,对比分析了a-C:H薄膜和a-C:H:Fe薄膜的沉积速率、表面形貌、热稳定性和光学带隙变化。研究表明：相同制备条件下,相比a-C:H薄膜,a-C:H:Fe薄膜的沉积速率高,表面颗粒小,容易碳化,光学带隙变窄。     

a-C:N:H纳米尖端荧光产生的机理

用CH4,H2和NH3为反应气体,利用等离子体增强热丝化学气相沉积在沉积有碳膜的Si衬底上制备了a-C:N:H纳米尖端,并用扫描电子显微镜和微区Raman光谱仪对碳膜和纳米尖端进行了表征。结果表明:Raman谱中含有与碳和氮相关的峰,且纳米尖端的Raman谱比碳膜的Raman谱有很强的荧光背景。Raman谱中的峰说明沉积的碳膜和纳米尖端是a-C:N:H薄膜和a-C:N:H尖端。a-C:N:H纳米尖端的Raman谱中强荧光背景的产生表明其在激发光源照射的过程中发射了强荧光,对a-C:N:H纳米尖端产生强荧光的机理进行了探讨。     

a-C:F薄膜的热稳定性与光学带隙的关联

以CF4和C6H6的混合气体作为气源,在微波电子回旋共振化学气相沉积(ECRCVD)装置中制备了氟化非晶碳薄膜(aC:F),并在N2气氛中作了退火处理以考察其热稳定性.通过傅里叶变换红外吸收谱和紫外可见光谱获得了薄膜中CC双键的相对含量和光学带隙,发现膜中CC键含量与光学带隙之间存在着密切的关联,在高微波功率下沉积的氟化非晶碳膜具有低的光学带隙和较好的热稳定性. 关键词： 氟化非晶碳膜 光学带隙 退火温度 热稳定性     

类金刚石a-C:H膜的热释氢和红外吸收研究

本文利用热释氢和红外吸收研究了H在非晶态碳(a-C:H)膜中的含量和组态。实验结果表明,随着样品制备时衬底温度的增大:1)H在a-C:H膜中的组态从两相结构过渡为单相结构;2)H在a-C:H膜中的含量单调减少;3)a-C:H膜中sP³/sP²键合比例单调增大。 关键词：     

a-C:H膜化学结构对光学性能的影响

选用体积分数为99.999 9%的H2及反式-2-丁烯(T2B)为工作气体,利用低压等离子体增强化学气相沉积法制备了a-C;H薄膜.利用傅里叶变换红外光谱仪和X射线光电子能谱对薄膜化学键和电子结构进行分析,并结合高斯分峰拟合分析了薄膜中sp3/sp2杂化键比值和sp3C杂化键分数.结果表明:薄膜中氢含量较高,主要以sp3C-H形式存在;工作气压越高,制备的薄膜中C=C键含量越少,薄膜中sp3/sp2杂化键比值和sp3C杂化键分数增加,薄膜稳定性提高.应用UV-VIS光谱仪,获得了波长在400～1 000 nm范围内薄膜的光吸收特性,结果显示:a-C:H薄膜透过率可达98%.光学常数公式计算得到工作压强为4～14 Pa时光学带隙在2.66～2.76之间,并均随着工作气压的升高而增大.结果表明,随工作气压的升高,薄膜内sp3键减小,从而促使透过率、光学带隙增大.     

a-C:H薄膜的光致发光

利用射频辉光放电法沉积a-C:H薄膜,研究不同测量温度、不同退火温度光致发光光谱的变化,以及光致发光光谱随光子能量的变化,实验表明:随着测量温度的升高发光效率降低,用非晶碳网络的二相系统模型对这些结果作了解释。另外,光致发光光谱也随着激发光能量的不同而变化,当激发光能量接近光学带隙E_opt时,发光强度最高。 关键词：     

溅射制备非晶氮化镓薄膜的光学性能

采用直流磁控溅射方法在不同的氩气-氮气（Ar-N₂）气氛中制备了非晶氮化镓（a-GaN）薄膜. X射线衍射分析（XRD）和拉曼光谱（Raman）表明薄膜具有非晶结构. 通过椭偏光谱（SE）得到薄膜的折射率和厚度都随着氩气分量的增多而增大. 紫外—可见光谱（UV-Vis）的测量得到,当氩气分量R,即Ar/（Ar+N₂）,为0%时,薄膜的光学带隙为3.90eV,比晶体GaN （c-GaN） 的较大,这主要是由非晶结构中原子无序性造成的;而当R关键词： 非晶氮化镓 溅射 光学带隙 带尾态     

电子回旋共振等离子体增强沉积氟化非晶碳薄膜的光学性质

用紫外可见光透射光谱(UV-VIS)并结合键结构的X射线光电子能谱(XPS)和红外谱(FTIR)分析,研究了电子回旋共振等离子体增强化学气相沉积法制备的氟化非晶碳薄膜的光吸收和光学带隙性质.在微波功率为140—700W、源气体CHF₃∶C₆H₆比例为1∶1—10∶1条件下沉积的薄膜,光学带隙在1.76—2.85eV之间.薄膜中氟的引入对吸收边和光学带隙产生较大的影响,吸收边随氟含量的提高而增大,光学带隙则主要取决于CF键的含量,是由于强电负 关键词： 氟化非晶碳薄膜 光吸收与光学带隙 电子回旋共振等离子体     

类金刚石膜不同能量下的离子注入

本文对等离子体气相沉积法制备的类金刚石膜(a-C:H)进行了离子注入研究。注入剂量固定为5×10⁵Ar/cm²,注入能量分别为50,100,140和180keV。离子注入前后分别作了红外吸收谱,Raman谱,光学能隙,氢含量和电阻率的测量。结果表明,注入离子破坏了膜中的C—H键,sp²和sp³态都减少,而(sp²/sp³)比值增大;光学能隙E_opt,电阻 关键词：     

沉积参数对碳氮化硅薄膜化学结构及光学性能的影响

利用微波电子回旋共振（MW ECR）等离子体增强非平衡磁控溅射法制备了碳氮化硅（SiCN）薄膜。研究结果表明：硅靶溅射功率和氮气流量对薄膜化学结构、光学、力学等性能有很大影响。傅里叶变换红外光谱（FT IR）和X射线光电子能谱（XPS）表征显示，随着硅靶溅射功率由150W增加到350W，薄膜中C Si N键含量由14.3%增加到43.6％; 氮气流量的增大（2～15sccm）易于形成更多的sp2C＝N键和sp1C≡N键。在改变硅靶溅射功率和氮气流量的条件下，薄膜光学带隙最大值分别达到2.1eV和2.8eV。     

Structural and optical properties of Fe-doped hydrogenated amorphous carbon films prepared from trans-2-butene by plasma enhanced metal organic chemical vapor deposition

Fe-doped hydrogenated amorphous carbon (a-C:H:Fe) films were deposited from a gas mixture of trans-2-butene/ferrocene/H₂ by plasma enhanced metal organic chemical vapor deposition. X-ray photoelectron spectroscopy, Fourier transform infrared spectra and Raman spectra were used to characterize the composition and the bonding structure of the a-C:H:Fe and a-C:H films. Optical properties were investigated by the UV–visible spectroscopy and the photoluminescence (PL) spectra. The Fe-doped films contain more aromatic structures and C=C bonds than the undoped films. The sp ² carbon content and sp ² clustering of the films increase, and aromatic-like rings’ structures become richer after Fe-doping. The Tauc optical gap of the a-C:H:Fe films become narrower by 0.3 eV relative to the value of the a-C:H films. The PL peak shifts from 2.35 eV of the a-C:H films to 1.95 eV of the a-C:H:Fe films, and the PL intensity of the a-C:H:Fe films is greatly enhanced. A deep level emission peak around 2.04 eV of the a-C:H:Fe films is observed.     

Hybrid Structures of a-C:H Films Covered with Ag Nanoparticles for Application in Photonics

Optics and Spectroscopy - In this paper, the optical density and photoluminescence (PL) spectra of thin-film hybrid structures based on amorphous hydrogenated carbon (a-C:H) with a wide (2.7 eV)...     

Transport and optical properties of amorphous carbon and hydrogenated amorphous carbon films

In this paper we report on the electrical and optical properties of amorphous carbon (a-C) and hydrogenated amorphous carbon (a-C:H) films. Resistivity of both types of films decreases with increase in temperature. At lower temperatures (60-250 K) the electron transport is due to variable range hopping for the a-C films. At higher temperatures (300-430 K) it is thermally activated for both types of films. Analysis of the heterojunction between diamond-like carbon (DLC) and bulk silicon (Si) leads to the conclusion that our a-C films are of n-type and our a-C:H films are of p-type. The optical measurements with DLC revealed a Tauc bandgap of 0.6 eV for the a-C films and 1-1.2 eV for the a-C:H films. An Urbach energy around 170 meV could be determined for the a-C:H films. Strain versus resistance plots were measured resulting in piezoresistive gauge factors around 50 for the a-C films and in between 100 and 1200 for the a-C:H films.     

Comparison of the X-ray photoelectron and electron-energy-loss spectra of the nitrogen-doped hydrogenated amorphous carbon bond

The composition of nitrogen-doped hydrogenated amorphous carbon (a-C : H : N) films grown in a magnetically confined rf plasma-enhanced chemical vapour deposition system has been determined by X-ray photoelectron spectroscopy (XPS) and compared with that determined using a combination of elastic recoil detection analysis, Rutherford back-scattering and nuclear reaction analysis. The importance of nitrogen doping or 'incorporation' in hydrogenated amorphous carbon (a-C : H) films is discussed in relation to the significant variation in the sp 2 -to-sp 3 ratio that takes place. At 7 at.% N in the a-C : H matrix, a critical change in the microstructure is observed, which governs the resulting mechanical, optical and electronic properties. Finally, the correlation between the sp 2 and sp 3 fractions determined by a non-destructive method of obtaining the bond fractions (XPS) and by electron-energy-loss spectroscopy is discussed, with a view to evaluating accurately the sp 2 fraction in a-C : H : N films.     

Microstructures and photoluminescence of hydrogenated amorphous carbon films produced by using organic hydrocarbon source

Thin layers of hydrogenated amorphous carbon were prepared by using organic hydrocarbon source, xylene (C₈H₁₀), in plasma-enhanced chemical vapor deposition (PECVD) system. The microstructures were characterized by using Fourier-transform infrared and Raman scattering spectra. The appearance of a sharp vibration signal in 1600 cm^-1 strongly suggests the existence of sp² carbon clusters with aromatic rings. With increasing the deposition rf power, the content of these aromatic structures is increased in the films. In contrast to a broad single PL peak in methane (CH₄)-baseda-C:H films, the PL band of xylene-based a-C:H films contains multiple peaks in blue-green light region, which is influenced by rf power. We tentatively attributed it to the radiative recombination of electron-hole pairs through some luminescent centers associated with aromatic structures. Received: 26 April 2000 / Accepted: 9 May 2000 / Published online: 13 September 2000     

常压化学气相沉积技术生长ZnO∶H薄膜的光学性质

采用常压金属有机物化学气相沉积技术(APMOCVD),以二乙基锌(DEZn)为Zn源,去离子水(H2O)为氧源,N2作载气,在外延ZnO薄膜的反应气氛中通入少量氢气,在cAl2O3衬底上生长出了ZnO∶H薄膜。用X射线双晶衍射和光致发光谱对ZnO∶H薄膜的结晶性能和光学性质进行表征。结果表明,ZnO∶H薄膜(002)和(102)面的Ω扫描半峰全宽分别为46.1 mrad和81.4 mrad,表明该薄膜具有良好的结晶性能；室温下,ZnO∶H薄膜具有较强的紫外光发射(380 nm),在低温10 K光致发光谱中观测到位于3.3630 eV处与氢相关的中性施主束缚激子峰(I4)及其位于3.331 eV处的双电子卫星峰(TES)。采用退火的方法,通过观测I4峰的强度变化,研究了氢在ZnO∶H薄膜中的热稳定性。发现随着退火温度的升高,I4峰的强度逐渐减弱,表明在高温下退火,氢会从ZnO薄膜中逸出。     

氢化非晶碳薄膜的光致发光线型及其激发能量依赖关系

本文报道了氢化非晶碳薄膜在2.9-4.5eV光激发下的发光谱。它的光致发光谱是无结构的不对称宽带,半宽度约为0.8eV。在低于3.56eV的光激发下,谱带的峰值能量随激发能量的降低明显红移。在安德森带结构和指数分布的带尾态密度的基础上,考虑了尾态中粒子的两种跃迁过程,实验的PL谱就可得到解释。并用这个简单模型计算了这种材料的光致发光谱特征。     

氢稀释对FTS沉积a-Si:H薄膜结构特性的影响

采用对靶磁控反应溅射技术,以氢气作为反应气体在不同的氢稀释比条件下制备了氢化非晶硅薄膜.利用台阶仪、傅里叶红外透射光谱、Raman谱和紫外-可见光透射谱测量研究了不同氢稀释比对氢化非晶硅薄膜生长速率和结构特性的影响.分析结果发现,利用对靶磁控溅射技术能够实现低温快速沉积高质量氢化非晶硅薄膜的制备.随着氢稀释比不断增加,薄膜沉积速率呈现先减小后增大的趋势.傅里叶红外透射光谱表明,氢化非晶硅薄膜中氢含量先增大后变小.而Raman谱和紫外-可见光透射谱分析发现,氢稀释比的增加使氢化非晶硅薄膜有序度和光学带隙均先增大后减小.可见,此技术通过改变氢稀释比R能够实现氢化非晶硅薄膜结构的有效控制.     

Structure and phase composition of thin a-C:H films modified by Ag and Ti

The structure and phase composition of thin a-C:H and a-C:H〈M〉 films (M = Ag, Ti, or Ag + Ti) have been studied by Raman and X-ray photoelectron spectroscopy. The a-C:H〈M〉 films were prepared by ion-plasma magnetron sputtering of a combined target of graphite and metal in an Ar–CH₄ gas mixture. The Raman spectra of these films indicate that their structure is amorphous. The a-C:H〈Ag + Ti〉 films have a more graphitized structure in comparison with pure a-C:H films and films containing only one metal. It is established that carbon in the a-C:H〈Ag + Ti〉 films is in the sp ², sp ³, and C=O states, which are characteristic of the a-C:H, a-C:H〈Ag〉, and a-C:H〈Ti〉 films. In addition, there are also ether (–C–O–C–) or epoxy (?C?O–) carbon groups in the a-C:H〈Ag + Ti〉 films. It has been revealed that silver atoms in the a-C:H〈Ag〉 and a-C:H〈Ag + Ti〉 films form no chemical bonds with carbon, oxygen, and titanium. Titanium in the a-C:H〈Ti〉 and a-C:H〈Ag + Ti〉 films exists in the form of titanium IV oxide (TiO₂).