Multiple facets of tightly coupled transducer-transistor structures

The ever increasing demand for data processing requires different paradigms for electronics. Excellent performance capabilities such as low power and high speed in electronics can be attained through several factors including using functional materials, which sometimes acquire superior electronic properties. The transduction-based transistor switching mechanism is one such possibility, which exploits the change in electrical properties of the transducer as a function of a mechanically induced deformation. Originally developed for deformation sensors, the technique is now moving to the centre stage of the electronic industry as the basis for new transistor concepts to circumvent the gate voltage bottleneck in transistor miniaturization. In issue 37 of Nanotechnology, Chang et al show the piezoelectronic transistor (PET), which uses a fast, low-power mechanical transduction mechanism to propagate an input gate voltage signal into an output resistance modulation. The findings by Chang et al will spur further research into piezoelectric scaling, and the PET fabrication techniques needed to advance this type of device in the future

On-chip Magnetoresistive Sensors for Detection and Localization of Paramagnetic Particles

This paper presents the work towards miniaturized magnetic biosensor array based on the detection of paramagnetic particles using the giant magnetoresistance (GMR) effect. GMR sensors have been studied for many years, but its application for on-chip integration and in complex configurations, as well as effective localization for Lab-On-Chip and Tissue Engineering applications is not yet explored. This work demonstrates the development of initial prototypes of 5 and 9 sensor GMR arrays of varying geometries and corresponding calibration and localization algorithms to detect and localize paramagnetic materials in 2D. The generation of a uniform magnetic field using a 16 magnet Halbach cylinder was also analyzed and optimized using FEA for different sensor configurations. Results show excellent localization for the fully calibrated 5 sensor arrays, with a mean (SD) error of 2.45 (1.61) mm for the ferrofluid as compared to 1.48 (1.14) mm for a strong ferromagnet for a 25×25mm2 array surface. The 9sensor array similarly showed good results for full calibration

Spintronic Nanodevices for Neuromorphic Sensing Chips

Recent developments in spintronics materials and physics are promising to develop a new type of magnetic sensors which can be embedded into the silicon chips. These neuromorphic sensing chips will be designed to capture the biomagnetic signals from active biological tissue exploited as brain-machine interface. They lead to machines that are able to sense and interact with the world in humanlike ways and able to accelerate years of fitful advance in artificial intelligence. To detect the weak biomagnetic signals, this work aims to develop a CMOS-compatible spintronic sensor based on the magnetoresistive (MR) effect. As an alternative to bulky superconducting quantum interference device (SQUID) systems, the miniaturised spintronic devices can be integrated with standard CMOS technologies makes it possible to detect weak biomagnetic signals with micron-sized, non-cooled and low-cost. Fig. 1 shows the finite element method (FEM)-based simulation results of a Tunnelling-Magnetoresistive (TMR) sensor with an optimal structure in COMSOL Multiphysics. The finest geometry and material are demonstrated and compared with the state-of-the-art. The proposed TMR sensor achieves a linear response with a high TMR ratio of 172% and sensitivity of 223 μV/Oe. The results are promising for utilizing the TMR sensors in future miniaturized brain-machine interface, such as Magnetoencephalography (MEG) systems for neuromorphic sensing

Wearable Capacitive-based Wrist-worn Gesture Sensing System

Gesture control plays an increasingly significant role in modern human-machine interactions. This paper presents an innovative method of gesture recognition using flexible capacitive pressure sensor attached on user’s wrist towards computer vision and connecting senses on fingers. The method is based on the pressure variations around the wrist when the gesture changes. Flexible and ultrathin capacitive pressure sensors are deployed to capture the pressure variations. The embedding of sensors on a flexible substrate and obtain the relevant capacitance require a reliable approach based on a microcontroller to measure a small change of capacitive sensor. This paper is addressing these challenges, collect and process the measured capacitance values through a developed programming on LabVIEW to reconstruct the gesture on computer. Compared to the conventional approaches, the wrist-worn sensing method offerings a low-cost, lightweight and wearable prototype on the user’s body. The experimental result shows that the potentiality and benefits of this approach and confirms that accuracy and number of recognizable gestures can be improved by increasing number of sensor

Magnetoelectronics: Electronic skins with a global attraction

Magnetic-field sensors integrated on electronic skins can provide an artificial magnetoreception that relies only on geomagnetic fields

Perovskite Photodiode for Wearable Electronics

Photodetectors are sensing devices that have been used for a broad range electromagnetic wave sensing applications. We are currently investigating the use of photovoltaic cells for implantable and wearable applications [1] [2]. In this work, we have demonstrated the use of CH3NH3PbI3-xClx perovskite materials for photo sensing applications in wearable electronic devices. Our photodetectors were fabricated from two different structures. The first involves the formation of a thin film perovskite material that is sandwiched between bottom and top contact electrodes, while the second involves using hole and electron transport layers between the bottom and top electrodes. Despite a poorer device stability, our experimental results confirmed that devices without an interlayer yield superior performance. Furthermore, AFM results show that the perovskite film formed on top of the PEDOT: PSS layer is non-uniform with more crystalline domains, while it has better surface coverage on top of bare ITO substrates [3] [4]

Switched Capacitor DC-DC Converter for Miniaturised Wearable Systems

Motivated by the demands of the integrated power system in the modern wearable electronics, this paper presents a new method of inductor-less switched-capacitor (SC) based DC-DC converter designed to produce two simultaneous boost and buck outputs by using a 4-phases logic switch mode regulation. While the existing SC converters missing their reconfigurability during needed spontaneous multi-outputs at the load ends, this work overcomes this limitation by being able to reconfigure higher gain mode at dual outputs. From an input voltage of 2.5 V, the proposed converter achieves step-up and step-down voltage conversions of 3.74 V and 1.233 V for Normal mode, and 4.872 V and 2.48 V for High mode, with the ripple variation of 20–60 mV. The proposed converter has been designed in a standard 0.35 μm CMOS technology and with conversion efficiencies up to 97–98% is in agreement with state-of-the-art SC converter designs. It produces the maximum load currents of 0.21 mA and 0.37 mA for Normal and High modes respectively. Due to the flexible gain accessibility and fast response time with only two clock cycles required for steady state outputs, this converter can be applicable for multi-function wearable devices, comprised of various integrated electronic modules

Modelling of Spintronic Nanodevices for Neuromorphic Sensing Chips

No abstract available

Arm Mbed – AWS IoT System Integration [Open access]

This project explores the different Internet of Things (IoT) architectures and the available platforms to define a general IoT Architecture to connect Arm microcontrollers to Amazon Web Services. In order to accommodate the wide range of IoT applications, the architecture was defined with different routes that an Arm microcontroller can take to reach AWS. Once this Architecture was defined, a performance analysis on the different routes was performed in terms of communication speed and bandwidth. Finally, a Smart Home use case scenario is implemented to show the basic functionalities of an IoT system such as sending data to the device and data storage in the Cloud. Furthermore, a Cloud ML algorithm is triggered in real time by the Smart Home to receive a prediction of the current Comfort Level in the room

Device Modelling of Silicon Based High-Performance Flexible Electronics

The area of flexible electronics is rapidly expanding and evolving. With applications requiring high speed and performance, ultra-thin silicon-based electronics has shown its prominence. However, the change in device response upon bending is a major concern. In absence of suitable analytical and design tool friendly model, the behavior under bent condition is hard to predict. This poses challenges to circuit designer working in the bendable electronics field, in laying out a design that can give a precise response in a stressed condition. This paper presents advances in this direction and investigates the effect of compressive and tensile stress on the performance of NMOS and PMOS transistor and a touch sensor comprising a transistor and piezoelectric capacitor