Hydrogen influence on the structure and properties of amorphous hydrogenated carbon films deposited by direct ion beam

The present work provides results for amorphous hydrogenated carbon (a-C:H) films grown by direct ion beam deposition method. Acetylene and its mixtures with hydrogen were used. The films were characterized by Rutherford backscattering spectrometry, elastic recoil detection, Raman spectroscopy, ellipsometry, infrared spectroscopy, and microhardness measurements. These techniques indicated that an admixture of hydrogen yields a lower deposition rate, a higher content of total and bounded hydrogen in the a-C:H films, and a lower film density. The optical and mechanical properties depend on both, hydrogen concentrations in the gas phase and in the films, and show a strong diamond-like component, which reaches maximum at 34 at.% of hydrogen. Further hydrogen dilution enhanced only sp² clustering and possible reduced a number of both sp³ and C-C sp³ bonds. We suppose that these effects (in the high hydrogen concentration range) are not only related to the ion irradiation difference between the light hydrogen and the much heavier carbon but also to the diffusion in the a-C:H films.     

Properties of amorphous carbon films deposited by ion beam methods

Amorphous carbon films were prepared by the ion beam sputtering of graphite, by the ion beam sputtering of graphite with simultaneous ion bombardment of the growing film, and by primary ion beam deposition using a beam from a methane- argon plasma. The films are semiconducting in nature, having band gaps of the order of 1 eV. A nuclear reaction involving an energetic (2 MeV) beam of ¹¹B⁺ was used to obtain hydrogen profiles of the films. It was found that the electrical, optical and mechanical properties of the films could be correlated with the hydrogen content. The observed properties are explained qualitatively in terms of amorphous semiconductor theory.     

Growth and properties of the ion beam deposited SiOx containing DLC films

In the present study SiO_x containing diamond-like carbon (DLC) films were synthesized by the closed drift ion source from hexamethyldisiloxane vapor. Kinetics of the growth of DLC films was investigated using optical emission spectroscopy (OES). Structure, chemical composition, electrical and optical properties of the synthesized films were studied. The effects of ion beam energy were investigated. The main atomic hydrogen Balmer series lines and the intense broad CH group related peak were detected in the OES spectra registered in-situ during SiO_x containing diamond-like carbon film synthesis. The intensity ratio of H-β/CH peaks increased with the increase of applied ion beam energy. It was explained by activation of the dissociation of the hexamethyldisiloxane molecules. Changes of the structure of the diamond-like carbon films were observed for the films deposited under intense dissociation conditions.     

Effect of ion beam irradiation on metal particle doped polymer composites

Polymethyl methacrylate (PMMA) was prepared by solution polymerization method. Different concentrations (10, 20 and 40%) of Ni powder were dispersed in PMMA and the composite films were prepared by casting method. These films were irradiated with 120 MeV Ni^10 + ions at a fluence of 5 × 10¹² ions/cm². Electrical, structural and chemical properties of the composites were studied by means of an LCR meter, X-ray diffraction, FTIR spectroscopy and SEM/AFM, respectively. The results showed that the conductivity increases with metal concentration and also with ion beam irradiation. This reveals that ion beam irradiation promotes the metal/polymer bonding and converts polymeric structure into hydrogen depleted carbon network. It was observed from XRD analysis that percentage crystallinity and crystalline size decrease upon irradiation. This might be attributed to rupture of some polymeric bonds, which is also corroborated with FTIR spectroscopic analysis. Ion beam tempts graphitization of polymeric material by emission of hydrogen and/or other volatile gases. Surface morphology of the pristine and irradiated films was studied by atomic force microscopy (AFM)/scanning electron microscopy (SEM). Result showed that the surface roughness increases after ion beam irradiation.     

Functionalization of ordered iron-based nanoparticles deposited on mesoporous films

Mesoporous films obtained by dip-coating, combining polycondensation of silicate species and organization of amphiphilic mesophases, were decorated with iron-based nanoparticles from iron aqueous solution. High-resolution transmission electron microscopy (HR-TEM) images and energy dispersive X-rays spectroscopy (EDS) analysis show that the nanoparticles have diameters between 5 to 10 nm and they are deposited in an ordered sequence exclusively on top of the mesoporous structure. Afterward, by irradiating the material with a hydrogen ion beam, the iron-based compound is functionalized, i.e., its physical-chemical properties are modified. X-ray photoelectron spectroscopy (XPS) showed that the iron oxides and hydroxides are reduced to metallic iron. The deposition of organized iron-based nanoparticles and further ion beam functionalization might open perspectives on the study and fabrication of complex new materials.     

Ion beam energy effects on structure and properties of diamond like carbon films deposited by closed drift ion source

In the present study DLC films deposited from acetylene gas by a closed drift ion source were investigated. Ion beam energy effects on structure as well as optical and electrical properties of the synthesized films were studied. Non-monotonic dependence of structure of the DLC films on ion beam energy was observed. The highest sp³/sp² ratio as well as highest optical transparency was observed in the case of the films synthesized by 500 eV energy ion beam. However, the bandgap of the DLC films synthesized by 500 eV energy ion beam was the lowest between all investigated samples, while resistivity non-monotonically decreased with increase of the ion beam energy. These results were explained by changes of the sp³/sp² ratio, structure of sp² bonded clusters as well as hydrogen content in the film due to the competition between the increased (decreased) ion beam energy and decreased (increased) ion/neutral ratio.     

Nanocrystalline SnO2 formation using energetic ion beam

Nanocrystalline tin oxide (SnO2) thin films grown by RF magnetron sputtering technique were characterized by UV-Visible absorption spectroscopy and Photoluminescence spectroscopy. From atomic force microscopic (AFM) and Glancing angle X-ray diffraction (GAXRD) measurements, the radius of grains was found to be approximately 6+/-2 nm. The thin films were bombarded with 250 keV Xe2+ ion beam to observe the stability of nanophases against radiation. For ion bombarded films, optical absorption band edge is shifted towards red region. Atomic force microscopy studies show that the radius of the grains was increased to approximately 8 +/- 1 nm and the grains were nearly uniform in size. The size of the grains has been reduced after ion bombardment in the case of films grown on Si. During this process, defects such as vacancies, voids were generated in the films as well as in the substrates. Ion bombardment induces local temperature increase of thin films causing melting of films. Ion beam induced defects enhances the diffusion of atoms leading to uniformity in size of grains. The role of matrix on ion beam induced grain growth is discussed.     

离子束技术沉积羟基磷灰石薄膜的结构及溶解性能

分别采用离子束溅射和离子束增强沉积技术,以烧结羟基磷灰石（HA）陶瓷为靶材,在纯钛金属基片表面沉积HA薄膜．X光电子能谱分析表明：薄膜中Ca、P、O元素的化学态与所用HA陶瓷靶材相接近;相比HA靶材,薄膜表面存在CO₃^2-．X射线衍射分析表明：沉积薄膜均为非晶态结构,经650℃退火处理转变为结晶磷灰石．在模拟体液中的溶解实验揭示：薄膜仅与溶液中Ca、P和O存在离子交换;薄膜易降解,浸泡10天,样品经历了降解、再沉积过程;相比离子束溅射沉积膜,离子束增强沉积膜具有加速沉积Ca、P的能力．     

The role of hydrogen in a-C:H films deposited from hexane or acetylene using direct ion beam deposition method

The present work provides results of amorphous hydrogenated carbon (a-C:H) films deposited by direct ion beam deposition method. Hexane (C₆H₁₄+H_delivery) or acetylene (C₂H₂) precursors and their mixture with hydrogen (H₂) were used. The films were characterized by Raman spectroscopy (RS), ellipsometry, and electrical resistance measurements. RS indicates increase in sp³/sp² bonding ratio and disorder in graphite clusters, upon increasing of hydrogen content (from 0% to 50% for acetylene precursor) in the deposition gas mixture. The opposite trend is observed when the hydrogen concentration exceeded 50% (for acetylene) or additional hydrogen was added (for hexane). The data of electrical resistance measurements support the correlations defined by RS.     

DC magnetron sputtering of Si to form SiO2 in low-energy ion beam

Silicon dioxide (SiO₂) films were deposited by magnetron sputtering and ion-beam oxidation (IBO) in separate zones at ambient temperature. The optical and structural characteristics of the films were analyzed by spectrophotometry, Fourier transform infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscope. The oxygen ratio in the ion beam and the energy of ion bombardment during deposition has strong influence on the optical and physical properties of SiO₂ films. The experimental results indicated that the IBO method could finely manipulate the structure and properties of the growing films.     

离子束辅助脉冲激光沉积硼碳氮薄膜

以烧结B4C为靶材料、在氮离子束辅助下用脉冲激光沉积方法制备了三元化合物硼碳氮（BCN）薄膜.用X光电子谱和傅立叶变换红外谱方法表征了制备的薄膜.结果表明,膜层中包含B-C、N-C、B-N键等复合结构,以B-C-N原子杂化的形式结合成键,而并非各种成分的简单混合.还探讨了成膜过程和相关机理,离子束中的活性氮有效地和脉冲激光对B4C靶烧蚀产生的硼和碳结合成键,氮离子束的辅助还能在一定程度上抑制氧杂质进入膜层,给衬底适当加温有利于提高氮的含量并影响薄膜的化学结构.     

Preliminary impurity analysis of CuInSe2 thin films using the elastic recoil detection method

Knowledge of impurities in thin films is important for fabrication and characterization of photovoltaic devices. The lightimpurity distribution in electrodeposited CuInSe₂ thin films has been investigated by an elastic recoil detection method using a 30 MeV ³⁵Cl beam and identifying the recoil masses using a time-of-flight technique. It was found that both oxygen and hydrogen were present and distributed uniformly throughout the thickness studied. Upper limits for carbon and nitrogen were also established. The energy spectra for oxygen and hydrogen were deconvolved to obtain the relative concentrations as a function of depth. Using the same technique, the compositional uniformity of Cu, In and Se was also determined, yielding results qualitatively consistent with that obtained by secondary ion mass spectroscopy.     

Amorphous transition metal carbides

Titanium carbide films were deposited by chemical vapor deposition from tris(2,2'-bipyridine)titanium. Other films of titanium carbide and niobium carbide were obtained by electron beam vaporization of the corresponding crystalline compound. X-ray and electron diffraction studies showed that the structure of the deposits ranged from microcrystalline to amorphous. The coatings were analyzed by secondary ion mass spectroscopy, Auger electron spectroscopy and electron spectroscopy for chemical analysis. The results of these studies lead to an understanding of the formation and nature of the films. The objective is to modify the mechanical properties of brittle transition metal carbides.     

Influence of hydrogen-doped MgO thin films on the discharge characteristics in plasma display panels

In order to improve the discharge characteristics of Magnesium Oxide (MgO) thin films, hydrogen was doped to MgO thin films using an ion plating technique. Changes in the surface morphology, crystal orientation, optical properties, secondary electron emission coefficient, and defect states were studied with increasing hydrogen flow rates during the growth using field emission scanning electron microscope, X-ray diffraction, ellipsometry, γ-focused ion beam, and photoluminescence analysis. The change in firing voltage and delay time in plasma display panels (PDP) with the hydrogen-doped MgO thin films were also investigated. The results indicated that optimal hydrogen doping conditions can affect the surface structure and defect states: resulting in a significant reduction in the firing voltage and delay time of the PDP.     

动态离子束混合制备的钛氧化物薄膜的AES和XPS研究

分别采用O 和Ar 离子束轰击的动态离子束混合技术,在不锈钢基体上制备钛的氧化物薄膜。经X射线光电子能谱(XPS)和俄歇电子能谱(AES)分析,研究这两种工艺制备薄膜的化学组成和价键状态。结果表明,采用动态离子束混合技术制备的薄膜,可形成与基体有组分梯度的界面过渡层,减小了薄膜内应力,同时薄膜与基体具有较好的热学相容性,从而提高了薄膜的附着性能。Ar 束轰击的动态离子束混合沉积钛的氧化物薄膜中,Ti主要以 4价存在,而O 束轰击的动态离子束混合沉积形成的钛氧化物薄膜中含有次价态的钛氧化物。     

Microanalyses on the hydrogen permeated 70% SiCC films

SiCC films with content of 70% SiC were deposited by rf magnetron sputtering on stainless steel or NaCl substrate followed by argon ion bombardment. Samples were then submitted to hydrogen permeation at 3.23×10⁷ Pa and 500 K for 3 h. Secondary ion mass spectroscopy (SIMS) was used to analyze hydrogen concentration with depth and to check the formation of hydrogen related bonds in the SiCC films with IR measurement. Auger electron spectra (AES) and X-ray photoelectron spectra (XPS) were carried out to check the effects of hydrogen participation on shifts of chemical bonding states of C, Si and O contamination.     

Intrinsic stress in diamond-like carbon films and its dependence on deposition parameters

The compressive stresses and the hydrogen content inside diamond-like carbon films were measured for various deposition conditions. Four methods of film deposition were tested: primary beam containing CH₄; primary beam containing CH₄ with simultaneous bombardment of second beam of energetic argon ions; primary beam containing C₄H₁₀, and sputter deposition of graphite with the addition of hydrogen gas. The compressive stresses in the films were attributed mainly to the bombarding energy of the ion beam. An additional contribution to the compressive stresses probably came from the complex species in the discharge. The contribution of the hydrogen to the stresses in the films did not seem to be obvious.     

Argon ion beam and electron beam-induced damage in Cu(In,Ga)Se2 thin films

Ar ion beam and electron beam-induced damages in Cu(In,Ga)Se₂ thin films are investigated by transmission electron microscopy and X-ray energy-dispersive spectroscopy. We find that a high-energy Ar ion beam can cause severe damage in Cu(In,Ga)Se₂ surface regions by preferentially depleting Se and In. The depletion can occur with an Ar ion beam at energy as low as 0.5 keV. High-energy electron beams also cause damage in Cu(In,Ga)Se₂ thin films by preferentially depleting In and Ga. Our results imply that special care must be taken for measurements involving surface treatments using high-energy Ar ion beams or electron beams.     

氧离子能量对离子束辅助沉积Al2O3薄膜的结构及光学性能的影响

利用氧离子束辅助脉冲反应磁控溅射技术在聚酰亚胺基底上沉积Al2O3薄膜。这项技术在溅射高纯铝靶材的同时利用低能氧离子进行氧化来控制薄膜的化学配比。研究了薄膜沉积过程中离子束辅助的作用以及离子束放电电压对Al2O3薄膜的化学成分、结构、表面形貌、光学性能以及沉积速率的影响。结果发现,离子束放电电压对薄膜的化学成分具有显著影响,当电压增加到200 V,薄膜已基本达到完全化学计量比且薄膜为非晶结构;薄膜表面粗糙度随着离子束放电电压的增加而减小,当电压达到300V时,薄膜具有最小的表面粗糙度;通过对Al2O3薄膜透射谱的测量,分析薄膜的光学特性,获得了薄膜的光学常数随离子束放电电压的变化规律,发现氧离子束辅助沉积的薄膜具有较高的折射系数和较低的消光系数;另外,薄膜的沉积速率在电压增加到300V时达到最大值70 nm/min,是未采用离子束辅助时沉积速率的5倍。     

Hydrophobic properties of the ion beam deposited DLC films containing SiOx

Diamond like carbon (DLC) films received considerable interest due to outstanding mechanical and tribological properties as well as chemical inertness and hydrophobicity. That combination is particularly interesting for possible application of the DLC as anti-sticking layers in novel lithographic techniques such as nanoimprint lithography, because Si, quartz and Ni - the most often used materials for imprint stamp formation - have high surface energy and, as a result, bad anti-adhesive properties. In present study, SiO_x containing DLC thin films were synthesized from hexamethyldisiloxane vapor and hydrogen gas mixture by direct ion beam deposition. Anti-sticking properties of the grown DLC thin films were evaluated measuring surface contact angle with water. Chemical composition and structure of the deposited films were investigated by X-ray photoelectron spectroscopy and FTIR spectrometry. Morphology of the films was measured by atomic force microscopy. Effects of hexamethyldisiloxane flux on structure, anti-sticking properties and surface morphology of the SiO_x containing DLC thin films were defined.