Transistor

About: Transistor is a research topic. Over the lifetime, 138090 publications have been published within this topic receiving 1455233 citations.

Electrosurgical generator and system for underwater operation

Abstract: A radio frequency generator for an electrosurgical system is provided, the system including an electrode assembly having two electrodes for use immersed in an electrically conductive fluid. The generator has control circuitry for rapidly reducing the delivered radio frequency output power by at least 50 % within at most a few cycles of the peak radio frequency output voltage reaching a predetermined threshold limit. In this way, tissue coagulation can be performed in, for example, saline without significant steam generation. The same peak voltage limitation technique is used in a tissue vaporisation or cutting mode to limit the size of the steam pocket at the electrodes and to avoid electrode burning. The generator has a push-pull output stage with a series-resonant output circuit, the output stage being driven by a radio frequency oscillator at a frequency which, in general, differs from the resonant frequency of the resonant output circuit. Power control is achieved by varying the ON-time of switching transistors forming the push-pull output pair and by altering the frequency spacing between the excitation frequency and the resonant frequency of the series-resonant output circuit. In an alternative embodiment, a bridge configuration using two push-pull pairs is used, yielding a further power control variable: the relative phase of the driving signals to the respective transistor pairs.

A single-atom transistor

Abstract: The ability to control matter at the atomic scale and build devices with atomic precision is central to nanotechnology. The scanning tunnelling microscope can manipulate individual atoms and molecules on surfaces, but the manipulation of silicon to make atomic-scale logic circuits has been hampered by the covalent nature of its bonds. Resist-based strategies have allowed the formation of atomic-scale structures on silicon surfaces, but the fabrication of working devices-such as transistors with extremely short gate lengths, spin-based quantum computers and solitary dopant optoelectronic devices-requires the ability to position individual atoms in a silicon crystal with atomic precision. Here, we use a combination of scanning tunnelling microscopy and hydrogen-resist lithography to demonstrate a single-atom transistor in which an individual phosphorus dopant atom has been deterministically placed within an epitaxial silicon device architecture with a spatial accuracy of one lattice site. The transistor operates at liquid helium temperatures, and millikelvin electron transport measurements confirm the presence of discrete quantum levels in the energy spectrum of the phosphorus atom. We find a charging energy that is close to the bulk value, previously only observed by optical spectroscopy.

Design of analog integrated circuits and systems

Abstract: MOS transistor models bipolar transistor models feedback and sensitivity in analogue integrated circuits elementary transistor stages behavioural modelling of operational and transconductance amplifiers operational amplifier design fundamentals of continuous-time and sampled-data active filters design and implementation of integrated active filters.

Taxel-Addressable Matrix of Vertical-Nanowire Piezotronic Transistors for Active and Adaptive Tactile Imaging

Abstract: Designing, fabricating, and integrating arrays of nanodevices into a functional system are the key to transferring nanoscale science into applicable nanotechnology. We report large-array three-dimensional (3D) circuitry integration of piezotronic transistors based on vertical zinc oxide nanowires as an active taxel-addressable pressure/force sensor matrix for tactile imaging. Using the piezoelectric polarization charges created at a metal-semiconductor interface under strain to gate/modulate the transport process of local charge carriers, we designed independently addressable two-terminal transistor arrays, which convert mechanical stimuli applied to the devices into local electronic controlling signals. The device matrix can achieve shape-adaptive high-resolution tactile imaging and self-powered, multidimensional active sensing. The 3D piezotronic transistor array may have applications in human-electronics interfacing, smart skin, and micro- and nanoelectromechanical systems.

Solution-processed ambipolar organic field-effect transistors and inverters.

Abstract: There is ample evidence that organic field-effect transistors have reached a stage where they can be industrialized, analogous to standard metal oxide semiconductor (MOS) transistors. Monocrystalline silicon technology is largely based on complementary MOS (CMOS) structures that use both n-type and p-type transistor channels. This complementary technology has enabled the construction of digital circuits, which operate with a high robustness, low power dissipation and a good noise margin. For the design of efficient organic integrated circuits, there is an urgent need for complementary technology, where both n-type and p-type transistor operation is realized in a single layer, while maintaining the attractiveness of easy solution processing. We demonstrate, by using solution-processed field-effect transistors, that hole transport and electron transport are both generic properties of organic semiconductors. This ambipolar transport is observed in polymers based on interpenetrating networks as well as in narrow bandgap organic semiconductors. We combine the organic ambipolar transistors into functional CMOS-like inverters.