Jikui Luo

We present a type of high performance contact-separation mode triboelectric generators (TEG). The TEGs consist of a poly(vinylidene fluoride) composite with embedded barium titanate nanomaterial (PVDF-BaTiO3) and polyamide-6 (PA6). Additional BaTiO3 nanomaterial in the PVDF increase the relative permittivity and piezoelectric effect, thus enhance the performance of the TEGs. Owing to the increased energy storage capability, the PVDF-BaTiO3/PA6 TEG demonstrates a significantly higher voltage of 1040 V and charge density of 17.2 mu C/m(2), as compared to 440 V and 13.2 mu C/m(2) of the PVDF-PA6 TEG. The improvement in performance of the TEGs is attributed to not only the enhanced polarization of composite, but also the increased relative permittivity.

Recent developments in triboelectric nanogenerators (TENG) make self-powered sensors possible and realistic by harvesting waste mechanical energy from the environment. This paper focuses on brief introduction on the basic principles and various working modes of TENGs, theoretical study and numerical analysis on TENGs in contact and sliding working modes. Numerical analysis is conducted using MATLAB for KAPTON-PMMA (Poly(methyl methacrylate)) TENG models, working on sliding mode and contact mode. The dynamic output characteristics of sliding mode TENG are evaluated with the varying input resistance value and dielectric gap distance.

A novel flexible Film Bulk Acoustic Wave Resonators (FBARs) based on ZnO/PET structure was fabricated without back-etch. The PET layer is applied as acoustic reflector and substrate of FBAR. It has 1.14GHz parallel resonant frequency, 1.229GHz series resonant frequency and about 150 Q factors. The FBARs acoustic impedance is improved by using harden metal Au instead of AI as the bottom electrodes. The ZnO/PET structure FBAR is also simulated by COSMOL to confirm its working mechanism.

We present fluorinated ZnO (F-ZnO) TFT to overcome the native drawback of pure ZnO TFT. At a optimum F concentration of 10(20)/cm(3), it exhibits high field-effect mobility of 71cm(2)/Vs, low sub-threshold slope (SS) of 0.18V/decade, high reliability, good uniformity and light insensitivity, The improvement is attributed to the passivation effect of F. Based on the high performance F-ZnO TFTs, a novel active-matrix self-capacitive touch panel was firstly realized. This touch technology combined the functions of high precise stylus handwriting and sensitive multi-touch, which will be the trend of the development of the next-genaration high precision touch panel.

Over the last few years a number of sensing platforms are being investigated for their use in drug development, microanalysis or medical diagnosis. Lab-on-a-chip (LOC) are devices integrating more than one laboratory functions on a single device chip of a very small size, and typically consist of two main components: microfluidic handling systems and sensors. The physical mechanisms that are generally used for microfluidics and sensors are different, hence making the integration of these components difficult and costly. In this work we present a lab-on-a-chip system based on surface acoustic waves (for fluid manipulation) and film bulk acoustic resonators (for sensing). Coupling surface acoustic waves into liquids induces acoustic streaming and motion of micro-droplets, whilst it is well-known that bulk acoustic waves can be used to fabricate microgravimetric sensors. Both technologies offer exceptional sensitivity and can be fabricated from piezoelectric thin films deposited on Si substrates, reducing the fabrication time/cost of the LOC devices.

A novel temperature and pressure sensor based on a single film bulk acoustic resonator (FBAR) is designed. This FBAR support two resonant modes, which response opposite to the change of temperature. By sealed the back cavity of a back-trench membrane type FBAR with silicon wafer, an on-chip single FBAR sensor suitable for measuring temperature and pressure simultaneously is proposed. For unsealed device, the experimental results show that the first resonant mode has a temperature coefficient of frequency (TCF) of 69.5ppm/K, and the TCF of the second mode is -8.1ppm/K. After sealed the back trench, it can be used as a pressure sensor, the pressure coefficient of frequency (PCF) for the two resonant mode is -17.4ppm/kPa and -6.1 ppm/kPa respectively, both of them being more sensitive than other existing pressure sensors.

Coatings have been widely used in engineering and decoration to protect components and products and enhance their life span. Nickel (Ni) is one of the most important hard coatings. Improvement in its tribological and mechanical properties would greatly enhance its use in industry. Nanocomposite coatings of metals with various reinforced nanoparticles have been developed in last few decades. Titania (TiO2) exhibit excellent mechanical properties. It is believed that TiO2 incorporation in Ni matrix will improve the properties of Ni coatings significantly. The main purpose of the current work is to investigate the mechanical and anti-corrosion properties of the electroplated nickel nanocomposite with a small percentage of TiO2. The surface morphology of nanocomposite coating was characterized by scanning electron microscopy (SEM). The hardness of the nanocoating was carried out using micromaterials nanoplatform. The sliding wear rate of the coating at room temperature in dry condition was assessed by a reciprocating ball-on-disk computer-controlled oscillating tribotester. The results showed the nanocomposite coatings have a smoother and more compact surface than the pure Ni layer and have higher hardness and lower wear rate than the pure Ni coating. The anti-corrosion property of nanocomposite coating was carried out in 3.5% NaCl and high concentrated 35% NaCl solution, respectively. The results also showed that the nanocomposite coating improves the corrosion resistance significantly. This present work reveals that incorporation of TiO2 in nickel nanocomposite coating can achieve improved corrosion resistance and mechanical properties of both hardness and wear resistance performances, and the improvement becomes stronger as the content of TiO2 is increased.

Whole chip electrostatic discharge (ESD) protection for 2.4 GHz low noise amplifier (LNA) under 0.18 mu m radio frequency (RF) CMOS process is proposed in this paper. Complementary silicon controlled rectifier (SCR) with different layouts for I/O pad ESD protection is evaluated and compared with traditional SCR and diode. Results show that the island complementary SCR (MSCRIsland) structure has highest figure of merit (FOM) and its ESD protection for RF I/O passes 6 kV human body model (HBM), while extra 0.28 dB noise figure (NF) and 178 fF capacitance is introduced into LNA by this ESD protection. LNA power clamp ESD protection is also designed as RC triggered various devices, such as NMOS, SCR and their mixture. Results show that RC trigger NMOS-SCR has high robustness and turn-on speed and its power clamp protection passes 5 kV HBM.

The work reported here shows a direct experimental comparison of the sensitivities of AlN solidly mounted resonators (SMR)-based biosensors fabricated with standard metal electrodes and with carbon nanotube electrodes. SMRs resonating at frequencies around 1.75 GHz have been fabricated, some devices using a thin film of multi-wall carbon nanotubes (CNTs) as the top electrode material and some identical devices using a chromium/gold electrode. Protein solutions with different concentrations were loaded on the top of the resonators and their responses to mass-load from physically adsorbed coatings were investigated. Results show that resonators using CNTs as the top electrode material exhibited higher frequency change for a given load due to the higher active surface area of a thin film of interconnecting CNTs compared to that of a metal thin film electrode and hence exhibited greater mass loading sensitivity. It is therefore concluded that the use of CNT electrodes on resonators for their use as gravimetric biosensors is viable and worthwhile.

This paper describes a MEMS (micro-electromechanical systems) modulator suitable for optical system network signaling. Several actuator mechanisms exist that potentially satisfied this purpose, electrostatic actuation was identified as the most suitable for the application due to speed of operation and low power consumption. MEMS geometry and analytical mode models were developed and applications performance estimated including multiphysics phenomena. Finite element analysis was undertaken using the commercially available software suite, COMSOL (R), performing static and dynamic simulations and analyses in the time and frequency domains. The proposal is that the MEMS modulator would be integrated with other optical components encased in a hermetically sealed vacuum environment, resulting in a lightly damped response with decaying oscillation. A two-step drive signal was developed and simulated using the multidomain, simulation package SIMULINK (R). The optimized MEMS design and two-step driver realized a MEMS optical modulator meeting the required specification. Finally a proposal for integration within an optical transmitter assembly is described.