一种新的纳米结构--管状石墨锥

文章作者利用微波等离子体辅助化学气相沉积的方法在铁针尖上合成了一种新的纳米结构，并称之为管状石墨锥．管状石墨锥在外形上由多面锥体组成，其内部是同心的圆柱形石墨层，其空心的直径为几个纳米到几十个纳米．这些管状石墨层从内到外地逐渐变短，从而使得它们呈现出锥形外观．锥的顶角一般为6-7度左右，锥的尖端只有几个纳米大小，而锥的底部可达到微米量级．值得注意的是，组成管状锥体的石墨层具有惟一的手性，都表现为锯齿型。     

Plasma-polymerized thiophene films for enhanced rubber-steel bonding

Thin films of plasma-polymerized thiophene (PPTh) were deposited on cold-rolled steel substrates to improve adhesion to rubber compounds. PPTh films were characterized by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy. The ratio of carbon-to-sulfur found in PPTh films is 4:1, suggesting the monomer structure is generally intact, which was supported by FT-IR absorptions characteristic of polymerized thiophene rings. However, some fragmentation did occur to give acetylenic and aliphatic groups. Steel-rubber adhesion measurements, performed in accordance with the ASTM 429-B peel test, strongly depended on cleaning and pretreatment methods as well as film thickness. Best results were obtained on polished steel samples that were cleaned with acid, pretreated with a hydrogen/argon plasma, then coated with 50 Å of PPTh film. These samples exhibited a peel force of 14.3 N/mm, which is comparable to that of polished brass control samples. Depth-profiling XPS analysis of the rubber-steel interface showed the existence of an iron sulfide layer which is likely responsible for the strong adhesion.     

Dielectric Measurements of CVD Diamonds at Millimeter Wavelength Using a Fabry-Perot Open Resonator

Precise dielectric property measurements at a millimeter wave frequency band are attractive. A Fabry-Perot open resonator consisting of hemispherical and plane mirrors, coupling holes is designed by the use of analytic theories and a numerical simulation code. HFSS. Dielectric constant measurements on CVD diamonds are performed by a frequency variation method. Measurements show that permittivity and loss tangent range from 5.59 to 6.46, and from 1.1 × 10⁻³, to 5.3 × 10⁻². respectively, in the frequency range of 95–100 GHz depending on sample preparation of the CVD diamonds.     

激光抛光化学气相沉积金刚石膜

讨论了激光抛光金刚石膜机理、影响因素,分析了激光抛光金刚石膜理论模型、激光抛光后金刚石膜的粗糙度极限,提出要实现金刚石膜特别是厚膜的精密抛光须考虑激光辅助复合抛光或其它抛光工艺。     

热丝CVD法制备C—N薄膜的结构分析

用热丝 CVD法 ,以甲烷、氮气和氢气为气源 ,在 Si( 1 1 1 )衬底上沉积了C- N薄膜。用 X射线光电子谱 ( xps)、喇曼光谱 ( RS)、X射线衍射 ( XRD)和扫描电镜( SEM) ,对 C- N薄膜的结构及生长速率进行了分析研究。结果表明 :C- N薄膜的结构为非晶态 ,同时含有金刚石和石墨相 ;氮以三种不同的化学键合状态存在于膜中 ,其中 β键合状态的结合能与晶态 β- C3N4的结合能接近 ;随混合气体中氮气含量增加 ,C- N薄膜的生长速率减小。     

Sensitive and Ultrabroadband Phototransistor Based on Two‐Dimensional Bi2O2Se Nanosheets

Bi₂O₂Se, a high‐mobility and air‐stable 2D material, has attracted substantial attention for application in integrated logic electronics and optoelectronics. However, achieving an overall high performance over a wide spectral range for Bi₂O₂Se‐based devices remains a challenge. A broadband phototransistor with high photoresponsivity (R) is reported that comprises high‐quality large‐area ( ≈ 180 µm) Bi₂O₂Se nanosheets synthesized via a modified chemical vapor deposition method with a face‐down configuration. The device covers the ultraviolet (UV), visible (Vis), and near‐infrared (NIR) wavelength ranges (360–1800 nm) at room temperature, exhibiting a maximum R of 108 696 A W^?1 at 360 nm. Upon illumination at 405 nm, the external quantum efficiency, R, and detectivity (D*) of the device reach up to 1.5 × 10⁷%, 50055 A W^?1, and 8.2 × 10¹² Jones, respectively, which is attributable to a combination of the photogating, photovoltaic, and photothermal effects. The devices reach a ?3 dB bandwidth of 5.4 kHz, accounting for a fast rise time (τ_rise) of 32 µs. The high sensitivity, fast response time, and environmental stability achieved simultaneously in these 2D Bi₂O₂Se phototransistors are promising for high‐quality UV and IR imaging applications.     

石墨烯上生长GaN纳米线的研究

在常压条件下采用化学气相淀积(CVD)技术在有石墨烯插入层的衬底上生长GaN纳米线,研究了生长温度、石墨烯插入层、催化剂等因素对GaN纳米线的形貌、光学特性以及结构的影响.通过扫描电子显微镜(SEM)、光致发光(PL)谱、拉曼(Raman)谱和透射电子显微镜(TEM)等表征手段对GaN纳米线的形貌、光学特性以及结构进行表征.结果表明,在1 100℃条件下,同时有石墨烯插层和催化剂的衬底表面能够获得低应力单晶GaN纳米线.石墨烯、催化剂对于获得低应力单晶GaN纳米线有重要的作用.     

Preparation and characterization of highly dispersed V2O5/SiO2prepared by a CVD method

Highly dispersed V₂O₅/SiO₂(CVD catalyst) was prepared by the reaction of vaporized VO(OPrⁱ)₃ with silica at 293 K, whose process was followed by an IR technique. The rate of propylene photooxidation increased with an increase in V₂O₅ loading for CVD catalysts, but leveled off for impregnated ones. The CVD catalysts were characterized by XAFS and photoluminescence spectroscopy.     

Vapor phase modification of sol-gel derived titania (TiO2) surfaces

Chemical vapor deposition (CVD) method was used in titania surface modification. Titania layers were obtained in sol-gel process and prepared as thin films on silicon wafers in dip-coating method. In order to define the influence of modification on titania surface properties (e.g., friction), various types of fluoroalkylsilanes were used. The effectiveness of the modification was monitored by FT-IR spectroscopy. The topography and frictional measurements were investigated with the use of atomic force microscopy (AFM).     

工艺参数对真空紫外光直接光CVDSiO2—Si界面特性的影响

采用高频（１ＭＨｚ）Ｃ－Ｖ测试和红外谱，研究了工艺参数对ＸＣ激发真空紫外光直接光ＣＶＤＳｉＯ２的ＳｉＯ２／Ｓｉ界面特性的影响。结果表明，衬底温度Ｔｓ对固定氧化物电荷密度△Ｎｏｔ、慢界面态密度△Ｎ的影响比反应室总气压ＰＣ和ＳｉＨ４／Ｏ分压比显著。△Ｎｏｔ和△Ｎｓｔ在１１０℃附近有极小值。约为１０＾１０ｃｍ＾－１２量级。Ｔｓ〉１２０℃，△Ｎｏｔ呈正电荷性，Ｔｓ〈１１０℃，△Ｎｏｔ呈负电荷性，Ｓｉ－Ｏ－