UNIVERSITY of GLASGOW

Nanotechnology
 

    Nanoelectronics

    Image conveying smart dust researchSmart dust for remote planetary sensing

    Smart dust is envisaged as a swarm of motes: miniature communication/sensor devices linked by a wireless communications network. Nanotechnology can currently deliver smart dust motes on scales of 1 mm - 5 mm: comparable to medium to coarse sand grains on Mars.  Advances in nanotechnology will permit improvements in power management, sustainable energy supplies and powerful distributed sensing and computing. There have been many studies of how to deliver a mote swarm and how to communicate with such systems. Our work addresses the crucial problem of how dust motes can be given the ability to move around in their application environment.

    We are particularly interested in the potential use of smart dust swarms for remote planetary sensing. Our key new idea is the possibility of using adaptive shape-changing of smart dust motes in order to navigate within wind-blown transport above and on a remote planetary surface. Our studies include the application of electro-active polymer sheaths surrounding a mote to provide shape adaptation. Simulation studies are in progress to develop navigational algorithms to allow swarms to move collectively in a wind-borne environment. New concepts for wireless communications and long range communications are under development using experimental smart dust motes and system modeling.

    Contact: Prof John Barker

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    Simulation of nano-CMOS devices

    Nano CMOS deviceThe Device Modelling Group at Glasgow is one of the largest and best equipped device modelling groups in the world. The group develops one of the most advanced drift-diffusion, Monte Carlo and quantum simulators for nano scaled CMOS devices. The effect of strain, new channel materials, and high-k dielectric stacks are included in the simulators. The simulators are used to study nonequilibrium, ballistic and quantum effects in the present and next generations nanoelectronic devices and to design high performance transistors with conventional and novel device architecture. A particular strength of the group is the simulation of intrinsic parameter fluctuations in nano CMOS devices arising from the discreteness of charge and matter. Random discrete dopants, LER, interface roughness and the structure of the gate electros and the high-k dielectric are included as sources of fluctuations. The intrinsic parameter fluctuations are crucial for the design of the next generation circuits and systems.

    Contact:  Prof Asen Asenov, Prof John Barker

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    Heterostructure bipolar transistor technologies

    Nanometre-scale Heterostructure Bipolar Transistor devices with performance far beyond current capabilities are being developed at the University of Glasgow. These HBTs are suitable for mixed signal applications – involving analogue and digital signals. Key application areas include future ultra-broadband 160 Gbit/s fibre optic systems, imaging, security, sensing and secure communications for defence applications.

    Work focuses on the development of new submicron Indium Phosphide (InP) HBT device processes with significantly reduced device parasitics. The goal is a device technology to support mixed signal integrated circuit (IC) realisation at millimetre-wave (up to 300 GHz) and terahertz (beyond 300 GHz) frequencies. The team are also developing gallium-arsenide-on-insulator (GOI) HBTs with an Indium Gallium Phosphide (InGaP) emitter to assess the potential for integration of III-V electronics on a Silicon platform. Other work involves HBT based magnetic field and chemical sensors.

    Contact:  Dr E Wasige

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    Nano transistors

    For over a decade the Ultrafast MMIC group have been developing leading edge applications of both active and passive MMIC components that operate at greater than 100GHz.

    The team have developed the fastest transistor technology in Europe – an ultra wideband 3-Stage high performance low noise amplifier. It is based around a world leading 50nm T-gate InP-HEMT with an fT of 550Ghz and f max of 440GHz. The low DC power consumption of the technology together with its high uniformity make it ideally suited to array-based applications.

    The Low Noise Amplifier provides improved performance compared to currently available commercial products for all key performance metrics including; Frequency range, Gain, Noise and Power Consumption.

    Contact:  Prof Iain Thayne

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    Nanoelectromagnetics

    Numerical solutions to classical electromagnetics have shown great accuracy in predicting the performance of complicated structures that have dimensions of size similar to the wavelength, such as antennas, waveguides and electromagnetic bandgaps to name but a few. However, akin to the way that conventional mechanics fails to predict quantum effects in active devices such as transistors, classical electromagnetic approaches may insufficiently describe the electromagnetic performance of nanoscale passive devices. A commercially relevant example is the performance of end-of-the-roadmap integrated circuit interconnects. We are interested in new techniques for fabricating, measuring and modelling nanoscale electromagnetic structures.

    Contact: Tim Drysdale, David Cumming, Iain Thayne, John Williamson

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    Terahertz microtechnology

    Terahertz technology is rapidly expanding to provide tools for imaging and spectroscopy.  We have built a formidable level of expertise in the design, construction and test of passive components for use in these systems.  Our design capability is based on varying levels of analysis from analytical estimates through to detailed numerical simulations using methods such as finite-difference time-domain.  Devices are made using either high precision machine tools (e.g. CNC mill) or more sophisticated microfabrication techniques (e.g. ICP etching) according to the wavelength of operation.  To date we have developed artificial dielectrics, polarisation compensators, tuneable electromagnetic bandgap filters, beam steerers and an assortment of other components. Test and measurement is achieved in-house using either our millimetre-wave analysers or a terahertz FTIR.  We have also collaborated extensively with other leaders in the field.

    Contact:  Prof David Cumming, Dr Timothy Drysdale

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    Quantum transport theory of nanostructures

    A range of cross-disciplinary analytical and numerical computational methods are being developed for the theory and modelling of the transport properties of nanostructures including semiconductor nanowire devices, ultra-small transistors, carbon nanotubes and molecular electronics. The methodologies include: Wigner function and Non-Equilibrium Green function methods, density functional theory and density matrices. A particular emphasis is placed on 2D and 3D modelling. The present theoretical formalisms can handle quantized vortex flows  and dissipative scattering. Extensive collaboration is made with other local and international groups in quantum chemistry and quantum transport theory. The work of this group underpins the study of ultra-small devices within the Device Modelling Group. New models have been developed to explore the physics of atomistic scattering on discrete impurities, non-linear screening and many-body interface effects on scattering mechanisms close to interfaces with source and drain and remote Coulomb scattering with gate regions. New models have been developed for surface roughness scattering and for interference scattering.

    Contact: Prof John Barker

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