Diamond-like carbon thin films by microwave surface-wave plasma CVD aimed for the application of photovoltaic solar cells

The nitrogen doped diamond-like carbon (DLC) thin films were deposited on quartz and silicon substrates by a newly developed microwave surface-wave plasma chemical vapor deposition, aiming the application of the films for photovoltaic solar cells. For film deposition, we used argon as carrier gas, nitrogen as dopant and hydrocarbon source gases, such as camphor (C₁₀H₁₆O) dissolved with ethyl alcohol (C₂H₅OH), methane (CH₄), ethylene (C₂H₄) and acetylene (C₂H₂). The optical and electrical properties of the films were studied using X-ray photoelectron spectroscopy, Nanopics 2100/NPX200 surface profiler, UV/VIS/NIR spectroscopy, atomic force microscope, electrical conductivity and solar simulator measurements. The optical band gap of the films has been lowered from 3.1 to 2.4 eV by nitrogen doping, and from 2.65 to 1.9 eV by experimenting with different hydrocarbon source gases. The nitrogen doped (flow rate: 5 sccm; atomic fraction: 5.16%) film shows semiconducting properties in dark (i.e. 8.1 × 10^{− 4} Ω^{− 1} cm^{− 1}) and under the light illumination (i.e. 9.9 × 10^{− 4} Ω^{− 1} cm^{− 1}). The surface morphology of the both undoped and nitrogen doped films are found to be very smooth (RMS roughness ≤ 0.5 nm). The preliminary investigation on photovoltaic properties of DLC (nitrogen doped)/p-Si structure show that open-circuit voltage of 223 mV and short-circuit current density of 8.3 × 10^{− 3} mA/cm². The power conversion efficiency and fill factor of this structure were found to be 3.6 × 10^{− 4}% and 17.9%, respectively. The use of DLC in photovoltaic solar cells is still in its infancy due to the complicated microstructure of carbon bondings, high defect density, low photoconductivity and difficulties in controlling conduction type. Our research work is in progress to realize cheap, reasonably high efficiency and environmental friendly DLC-based photovoltaic solar cells in the future.     

采用微波技术制备玻璃化温度渐变的EP/PU梯度功能材料

采用微波固化技术，制备了环氧树脂／聚氨酯梯度功能材料（EP／PU）FGM。分别采用扫描电镜（SEM）和傅立叶变换红外光谱仪（FTIR）对该梯度材料的形貌、结构进行了表征；并对材料的玻璃化转变温度和机械性质进行了测定。该FGM厚11．2mm，PU和EP层分别为2mm，过渡部分每层约为1mm。沿梯度方向，弹性模量变化范围可从0．069GPa到3．2GPa，玻璃化转变从160℃到-54℃，拉伸强度沿梯度方向也呈现渐变，从4．65MPa到64．8MPa。     

锌酞菁的微波合成及牛白蛋白测定研究

以邻苯二腈、硫酸锌为原料,采用微波固相法合成了锌酞菁。将锌酞菁磺化所得的磺酸基锌酞菁溶液与牛白蛋白作用将导致共振瑞利散射显著增强。在470nm处存在一共振散射强峰,牛白蛋白在0.25～20μg/mL的浓度范围内与散射强度（ΔI）呈线性关系,磺酸基锌酞菁溶液对牛白蛋白的检测限为0.17μg/mL,并且方法有较好的选择性。由此建立一种用共振散射光谱测定牛白蛋白的简便、快速的新方法。     

微波介质陶瓷及其展望

综述了微波介质陶瓷材料的特性和发展现状，介绍了几种重要的微波介质陶瓷体系，讨论了微波介质陶瓷性能的影响因素，指出了改善其性能的途径和微波介质陶瓷的预期进展。     

Effects of buffer layer materials and process conditions on growth mechanisms of forming networks of SWNTs by microwave plasma chemical vapor deposition

This study investigates the growth mechanism of IC compatible processes and to the feasibility of synthesizing networks of single-walled carbon nanotubes (SWNTs) at lower temperatures (610 °C) on Si wafer using microwave plasma chemical vapor deposition (MPCVD) with CH₄ and H₂ as source gases. The effects of the buffer layer materials (ZnS–SiO₂, Al₂O₃, AlON, and AlN ) and process conditions on growth of carbon nanostructures with Co as catalyst were also examined, where the buffer layers and Co catalyst were deposited in sequence by physical vapor deposition (PVD), followed by H-plasma pretreatment before deposition of carbon nanostructures. Additionally, the morphologies and bonding structures of carbon nanostructures were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), and Raman Spectroscopy. Analytical results demonstrate that networks of SWNTs are more favorable to be synthesized by selecting proper buffer layer material (e.g., AlON), and under higher temperatures, thinner catalyst thickness (e.g., 5 nm) and lower CH₄ / H₂ ratio (e.g., 5 / 100 sccm/sccm). The networks of SWNTs can be fabricated at temperatures as low as 610 °C by manipulating these parameters. In conclusion, the growth mechanism determines the conditions for the formation of nano-sized extrusions on catalyst particles surface.     

Synthesis of nitrogen incorporated diamond-like carbon thin films using microwave surface-wave plasma CVD

Nitrogenated diamond-like (DLC:N) carbon thin films have been deposited by microwave surface wave plasma chemical vapor deposition on silicon and quartz substrates, using argon gas, camphor dissolved in ethyl alcohol composition and nitrogen as plasma source. The deposited DLC:N films were characterized for their chemical, optical, structural and electrical properties through X-ray photoelectron spectroscopy, UV/VIS/NIR spectroscopy, Raman spectroscopy, atomic force microscope and current–voltage characteristics. Optical band gap decreased (2.7 to 2.4 eV) with increasing Ar gas flow rate. The photovoltaic measurements of DLC:N / p-Si structure show that the open-circuit voltage (V_oc) of 168.8 mV and a short-circuit current density (J_sc) of 8.4 μA/cm² under light illumination (AM 1.5 100 mW/cm²). The energy conversion efficiency and fill factor were found to be 3.4 × 10^{− 4}% and 0.238 respectively.     

微波辅助提取藜蒿黄酮的研究

进行了微波辅助提取藜蒿总黄酮的实验。分别采用单因素法和正交实验法探讨了各因素的影响。结果得到微波辅助萃取藜蒿总黄酮的最佳工艺条件为：固液比为1g：25mL，溶剂乙醇浓度为20％，微波功率为320W，辐射时间60s，溶液pH为10，此时藜蒿总黄酮提取率最高，约为0．870％。     

Microwave-assisted desulfurization of NOx storage-reduction catalyst

The activity of NO_x storage-reduction (NSR) catalysts is greatly reduced by sulfur poisoning, caused by the SO₂ present in the exhaust stream. Desorption of sulfur species from poisoned NSR catalysts occurs at temperatures in excess of 600 °C using reducing atmospheres and conventional heating. In this work, microwave (MW) heating has been used to promote desulfurization of poisoned NSR catalysts. The experiments were carried out by heating the catalyst with MW radiation and using hydrogen as the reducing gas. Desorption of H₂S at 200 °C was observed. Desorption at even lower temperatures (150 °C) was observed when water was introduced to the system. In the presence of water, sulfur species desorbed as both H₂S and SO₂. An overall reduction of sulfur species of about 60% was obtained. The use of MW heating proves to be an efficient way to achieve regeneration of poisoned NSR catalysts.     

镁碳材料中原位合成ZrB2 的研究

用化学纯ZrO2和硼酸(H3BO3)以及工业铝粉为原料,首先采用微波合成的方法确定原位合成ZrB2的最佳原料配比为m(ZrO2):m(H3BO3):m(Al)=3:6:20,然后在不同温度下(分别为850℃、950℃、1050℃、1150℃、1250℃和1350℃)分别保温3h,在镁碳材料中原位合成ZrB2,并用XRD、SEM和EDAX对合成后的试样进行分析。试验结果表明:在850℃的反应温度下,ZrO2不能转化成ZrB2;ZrO2从950℃开始转化成ZrB2,并且随着温度升高,ZrO2转化成ZrB2的量越多。从SEM可以看出,在较高温度下,ZrB2分布在石墨周围,对石墨起到很好的包覆作用。     

干燥机的最新发展(二)

本文论述了以过热水蒸汽作为干燥介质代替热风的干燥新技术的原理、优越性、存在的问题以及发展前景，并对微波对流干燥器的原理、特点等作了描述。