One of the major limitations in the development of ultrasensitive electrochemical biosensors based on one dimensional nanostructures is the difficulty involved with uniform growth of the nanofibers. Fabrication of the Vertically Aligned Carbon Nano Fibers (VACNFs) involve treatment of several chemicals including a variety of etchants. In previous work, successful measurement and characterization of electron beam patterned VACNFs is demonstrated using Atomic Force Microscopy. In this paper, the effect of etchant on VACNFs dimension (height and diameter) is observed and characterized using a highly sensitive and precise Atomic Force Microscopy (AFM). Furthermore, statistical analysis is performed on AFM measured data to demonstrated data confidence.

One of the major limitations in the development of ultrasensitive electrochemical biosensors based on one-dimensional nanostructure is the difficulty involved with reliably fabricating nanoelectrode arrays (NEAs). In previous work, a simple, robust and scalable wafer-scale fabrication method to produce multiplexed biosensors is introduced. Each sensor chip consists of nine individually addressable arrays that uses electron beam patterned vertically aligned carbon nanofibers (VACNFs) as the sensing element. To ensure nanoelectrode behavior with higher sensitivity, VACNFs were precisely grown on 100 nm Ni dots with 1 ¿m spacing on each micro pad. However, in order to examine the quality and measure the height and diameter of the VACNFs, some surface detection and measurement tool at the nanoscale level is needed. In this paper, we introduce an approach to measure these nano-scale features through atomic force microscope (AFM). With this method, both the 2D and 3D images of sample surface are generated and the sizes of carbon nanofibers and cavities are obtained. Furthermore, statistical analysis is carried out to enable improvement of VACNFs growth and fabrication.

In this paper, we present a new mathematical model for designing micro electrode geometry and electric field for carbon nanotubes application. The micro electrode design is based on the assumption that the electrical potential at any point (x,y,z) created by a micro electrode of interest is defined by a polynomial that obeys Laplacepsilas equation. By substituting this polynomial into Laplacepsilas equation the corresponding equipotentials can therefore be determined, and these in turn can be used to define the required micro electrode boundaries for use in carbon nanotube deposition, manipulation, and implementation using dielectrophoresis for electronics and sensing application. Simulation and preliminary experimental results are presented for the developed models.

This paper introduces our recently developed high precision robot localization system employing position sensitive detectors (PSD). A lateral effect PSD is an ideal position sensitive device with a resolution of approx. 0.5 mum. Such a device can be used to enhance the precision capabilities of robot localization or robot calibration. The developed PSD guided localization system is comprised of a structured laser pointer system attached to the robot end-effector and a PSD fixture. It is capable of feeding back the movement information of the TCP relative to the PSD frame. This is achieved by detecting the position of the laser beams emitted from the laser pointers onto the PSD surface. The system was well designed, mapped, and constructed and hence allows it to perform precision localization of the robot. Simulations and preliminary experiments demonstrated the effectiveness of the developed PSD guided localization system including hardware, software, and algorithms. Therefore, it is capable of improving the localization performance of robots as well as promoting the application of precision robot calibration.

This paper presents a novel automated manufacturing process for mass production of nano devices from advanced material such as carbon nanotubes (CNTs). CNTs have been found to be a promising and advanced material for nanoelectronics due to their size and excellent mechanical and electrical properties. Conventional electronic devices replaced by CNT are possibly to be miniaturized, and CNT based nano devices can provide better performance. Therefore, researchers have focused on developing different methods to manufacture CNT based nano devices in recent years. Since the size of CNTs is in nano scale, traditional robotic manipulation cannot be applied. Electrical assembly of CNT based devices is one of the promising methods to manipulate CNT to desired position. Building nano device by a single CNT is challenging, therefore, most people have concentrated on manipulating bundled CNTs. However, the electrical properties of bundled CNTs are difficult to control. As a result, device cannot benefit from quantum properties of a single CNT. Therefore, an automated process for manufacturing single CNT based nano devices is necessary for this application. A CNT deposition system is developed to manipulate a single CNT across microelectrodes precisely and repeatedly by using dielectrophoresis (DEP). Moreover, certain types of CNTs can be selected by using a micro chamber to filter other unnecessary types of CNTs. The system can potentially be used to fabricate an array of CNT based devices, and a fast and feasible batch nano assembly of consistent nano devices can be achieved.

Carbon nanotubes (CNTs) are good candidates for many electronics and sensing applications. These applications will require moving (deposit) and orienting carbon nanotubes to specific location, and separating CNTs with semiconducting and metallic band structure. In this paper, a new mathematical model describing precisely the rotational motion of carbon nanotubes in viscous medium (acetone) is presented. This new mathematical model correctly assumes that carbon nanotubes form a line shape after undergoing AC electric field compare to existing model that assumes carbon nanotubes to be a spherical particle. The new mathematical model is based on a newly developed model for applied torque due to electrorotation. It is also a method for controlled assembly of the CNTs on microstructures that have the plausibility to be scaled to wafer- level manufacturing. Simulation results are presented for the developed models. The developed model can be used to detect the position of carbon nanotubes and further implemented in the separation of semiconducting and metallic band structure carbon nanotubes.

In this paper, a new pneumatic end effector system for micro/nano fluidic handling, nanomanufacturing, and micro/nano manipulation is presented. The new micro pneumatic end-effector system consists of a DC micro-diaphragm pump and compressor, one region of flexible latex tube, a Polyvinylidene Fluoride (PVDF) sensor for in-situ measurement of micro force, and a micro steel tip. The micro steel tip of the new pneumatic end effector system has an internal diameter (ID) of 20 mum used for handling nano entities such as carbon nanotubes, DNA, micro/nano particles as well as for microfluidic handling and droplet control. The DC micro-diaphragm pump is automatically controlled via a voltage driver interfaced with a computer in order to effectively and efficiently control suction force and pressure during microfluidic handling and droplet control in nano manufacturing. The new pneumatic end effector system with force sensing can significantly improve the success rate for handling/depositing micro/nano entities in the case of carbon nanotubes. The experimental results show the success rate of placing carbon nanotubes between electrodes can reach close to 80%. Ultimately, the technology will provide a critical and major step towards the development of automated manufacturing process for batch assembly of micro devices, manufacturing of nano devices, microfluidic droplet control, and drug delivery

This paper aims at investigating and characterizing force behavior and mechanical properties of living drosophila embryos using an in situ modeled PVDF (polyvinylidene fluoride) piezoelectric microforce sensing tool with a resolution in the range of sub-muN. Drosophila embryo is one of the most studied organisms in biological research, medical research, genetics and developmental biology, and has implications in the cure of human diseases. In order to achieve high efficiency and accuracy during microinjection of genetic material into a drosophila embryo, it is absolutely necessary to allow close monitoring of the magnitude and direction of microinjection forces acting on the embryo during injection. In this paper, a microrobotic biomanipulation platform integrating a two-axis (2-D) modeled PVDF micro-force sensor is used to implement force sensing during microinjection of living drosophila embryos. Micro injection forces and membrane deformation of embryos in different stages of embryogenesis are found. Ultimately, the technology will provide a critical and major step towards the development of automated biomanipuation for batch microinjection of living embryos in genetics

This paper aims at developing an active force sensing technology for micromanipulation and microassembly using in-situ piezoelectric polyvinylidene fluoride (PVDF) films symmetrically bonded to the surface of a flexible cantilever beam structure. The designed micro-force sensing beam has both sensing and actuating layers. The sensing layer can detect the deformation signal due to the external micro-force acting at the sensor tip, the signal is then fed back to the actuating layer through a servoed transfer function or servo controller, as a result, a counteracting bending moment generated by the actuating layer can be used to balance the deformation of sensor beam in real time. Once balanced, the sensor tip will maintain in the equilibrium position as if the sensor stiffness is virtually improved, yielding accurate motion control of the sensor tip. Especially, the micro-force can be obtained by calculating the balance force through the counteracting servo voltage applied to the actuating layer. The developed active structure greatly enlarge dynamic range of micro-force sensor and enhance the manipulability during micromanipulation/microassembly when the sensor is mounted at the end-effector. Preliminary calibration and experimental results both verified the performance of the developed active micro-force sensor and the effectiveness of the models.

This paper aims at developing a force-guided micromanipulation technology with in-situ PVDF beam force sensing and hybrid force/position control based on an infinite dimensional system model. By using the designed PVDF force sensing cantilever composite structure with high sensitivity, the micro contact force/impact signal and its derivative can be extracted and processed. As the sensor structure installed at the end of micromanipulator is a soft beam, when manipulation is performed, the cantilever beam is necessary to be considered as a distributed parameter flexible link, then we developed a hybrid micro contact force/position control scheme on the basis of an infinite dimension system model. Experimental results verify the performance of the developed micro force sensing and hybrid control scheme. Ultimately the technology will provide a critical and major step towards the development of automated manufacturing processes for batch assembly of micro devices.

This paper aims at advancing micromanipulation technology with in situ polyvinylidene fluoride (PVDF) piezoelectric force sensing during microassembly and packaging process. Based on the previously developed PVDF 1-D sensor, by employing the parallel beam structure, a novel 2-D force sensor with relatively high natural frequency and sensitivity is optimally designed. The sensor can detect micro force and force rate signals, which can be fed back so as to greatly, improve the reliability of microassembly. Preliminary calibration and experimental results on assembly of surface MEMS devices both verified the performance of the new 2-D sensor that demonstrates a high sensitivity and a resolution in the range of /spl mu/N. Ultimately the technology would provide a critical and major step towards the development of automated micro-manufacturing processes for batch assembly of micro devices.