Distribution of electric field for carbon nanotube assembly: Experiments (II)

The distribution effect of electric field on the alignment and attachment of carbon nanotubes (CNTs) were investigated. The experimental results were compared with the simulation results according to three different shaped electrodes. In previous simulation, the round shaped electrodes were expected to be more effective for aligning and attaching a single CNT between two electrodes than conical or rectangular shaped electrodes. To verify the simulation results, three different shaped electrodes were introduced and a single multi-walled carbon nanotube (MWNT) was attached. The optimal conditions for aligning and attaching MWNTs such as the frequency, applied voltage and concentration of MWNTs solution were investigated. Through repeated experiments, frequency of 100 kHz-10 MHz, applied voltage of 0.3-1.3 Vrms/μm, concentration of 5 μg/mL in MWNTs solution were obtained as a possible condition range to attach MWNTs. Under these conditions, the yield of MWNTs attachment between two electrodes was up to 70%. In previous simulation, furthermore, it was verified that the size of the stable or quasi-stable region made CNTs aligned and attached on different shaped electrodes from the comparison of the experimental and simulation results. Most single MWNT attachment was accomplished on the round shaped electrodes.     

介电泳辅助水溶解抛光过程中微水滴分布的仿真与实验研究

目的 为解决KDP晶体无损表面的制造难题,进一步提升水溶解抛光方法的抛光质量和效率,研究介电泳效应对水溶解抛光液的影响.方法 提出一种介电泳辅助水溶解的抛光方法,最终获得超光滑表面,采用有限元软件模拟极化后微水滴的运动行为,并搭建验证性平台观测介电泳力作用下抛光液的吸附行为,验证抛光原理.之后数值模拟不同的电极形状对微水滴受到介电泳力的影响规律,优化得到最优电极形状参数.最后搭建试验平台,验证介电泳对水溶解抛光效率和质量的提升效果.结果 微水滴会在介电泳力作用下发生形变,并聚集在晶体表面附近,从而提高抛光过程中参与溶解的微水滴数量,加快溶解去除速率.同时,上电极也会对抛光液产生"吸附"作用,延长抛光液在晶体表面的作用时间,减小抛光液甩出率,进一步提高抛光效率.双螺旋结构电极具有最大的电场梯度,能够使水滴受到最大的介电泳力而向晶体表面聚集.经过20 min抛光后,采用传统水溶解抛光的KDP晶体表面粗糙度Ra由抛光前的590 nm降低至1.637 nm,而采用介电泳辅助水溶解抛光的KDP晶体,表面粗糙度降至1.365 nm,表面质量更高.与传统水溶解抛光相比,介电泳辅助水溶解抛光效率提升24％,同时能够更快地获得光滑表面.结论 在介电泳效应的辅助作用下,KDP晶体水溶解抛光质量和效率均得到了提升.     

Study on Assembly Method for GaAs Nanowires Device

The assembly and fabrication method for Gallium arsenide (GaAs) nanowires nano devices was implemented. Assembly of GaAs nanowires field effect transistor (FET) was realized by dielectrophoresis approach. Before deposition of the contacts, GaAs nanowires were treated wet etching in an ammonium polysulfide ((NH₄)₂S) solution to remove a surface oxide layer. The assembled devices were characterized by atomic force microscopy. The experimental results showed that the efficient assembly of GaAs nanowires was obtained when the applied alternating current voltage has a frequency of 1.5MHz and an amplitude of 10 V, and the success rate of ideal assembly for GaAs nanowires FET had been assessed. Meanwhile, it also provided an effective assembly method for other one-dimensional nanomaterials assembly of nano devices.     

High Yield Assembly of Cu/CuO Nanowires Device

The high yield assembly and fabrication method for Cu/CuO nanowires for nanoelectronic devices was implemented. Assembly of Cu/CuO nanowires nano-electronic devices were realized by floating potential and dielectrophoresis approach. The simulation of floating potential distribution of the chip was performed by comsol multiphysics coupling software. Six hundred devices were assembled on the area of less than one square centimeter. The assembled devices were characterized by scanning electron microscopy. The experimental results showed that high yield assembly had been realized, and the success rate of Cu/CuO nanowires ideal assembly for nanoelectronic devices had been assessed.     

MEMS白血病细胞介电电泳芯片的研究

研究了白血病细胞介电电泳芯片,其核心结构由绝缘覆盖层、电极层和绝缘垫层构成.该文对该芯片中的微电极进行了电场力学分析,讨论并设计了芯片的各个参数,应用微机电系统(MEMS)技术成功制备芯片,并对芯片进行了双列直插式DIP封装.文中研究的白血病细胞介电电泳芯片具有微型化,低电压驱动,对细胞无化学毒害等优点.     

Research on critical technology of micro/nano bioparticles manipulation platform based on light-induced dielectrophoresis

On the basis of the research on the status and problems of micro/nano bio-particles manipulation using dielectrophoresis, the theoretical basis and the model simulation of micro/nano bio-particles manipu-lation using light-induced dielectrophoresis were discussed. The space distribution of electric field and dielectrophoresis forces in different heights were also obtained. On this basis, the core component of the micro manipulation system, that is, photoconductive layer of the chip, was completed in the mat...     

Creation of Liquid Metal 3D Microstructures Using Dielectrophoresis

Patterning customized arrays of microscale Galinstan or EGaIn liquid metals enables the creation of a variety of microfabricated systems. Current techniques for creating microsized 3D structures of liquid metals are limited by the large dimension or low aspect ratio of such structures, and time‐consuming processes. Here, a novel technique for creating 3D microstructures of Galinstan using dielectrophoresis is introduced. The presented technique enables the rapid creation of Galinstan microstructures with various dimensions and aspect ratios. Two series of proof‐of‐concept experiments are conducted to demonstrate the capabilities of this technique. First, the 3D Galinstan microstructures are utilized as 3D microelectrodes to enhance the trapping of tungsten trioxide (WO₃) nanoparticles flowing through a microfluidic channel. Second, the patterned Galinstan microstructures are utilized as microfins to improve the dissipation of heat within a microfluidic channel that is located onto a hot spot. The presented technique can be readily used for creating customized arrays of 3D Galinstan microstructures for a wide range of applications.