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Electronics

carbon nanotube devices, nano- and organic electronics, integrated circuits based on Si nanowire transistors, nanoscale electron emitters, nanocomputing using quantum cellular automata, Schroedinger-Poisson solvers for nanotransistors.

Faculty involved:

Research Topics include:

Carbon Nanotubes

Carbon nanotubes, nanometer-diameter tubes made of carbon atoms, have been gaining ever-increasing popularity since their discovery in 1991 due to their outstanding electronic and mechanical properties. Nanotubes can be used in a wide range of applications including electronic devices such as quantum dots and transistors, electron emitters for flat-panel displays and electron-beam systems, chemical and biological sensors, light-weight composites and nanoscale actuators to name a few.

Flexible Electronics

Interconnects

Nano device modelling

Nano scale devices operate based on the principles of quantum mechanics. As a result, new models and methods are being developed to efficiently simulate these devices on today’s computers. Our group is developing these models and algorithms to simulate carbon nanotubes, nanowires, and quantum dots using quantum mechanics. We are exploring methods including molecular dynamics (MD), density functional theory (DFT), and non-equilibrium Green's functions (NEGF).

Nanowires

Organic Transistors

Quantum Dots

Quantum dots are nanostructures that are able to confine electrons, holes, or excitons in 3-dimensions. They can be realized using semiconductors, metallic islands, and through confinement of 2-dimensional electron gas (2DEG). Quantum dots are used in single electron transistors (SETs), tags for biological studies, lasers, and quantum-dot cellular automata (QCA).

Quantum-dot cellular automata (QCA)

Quantum-Dot Cellular Automata (QCA) is an exploratory computing paradigm in which information is encoded in the electronic charge configuration of a QCA cell. Each QCA cell can be constructed with a single molecule, coupled semiconductor quantum dots, metallic islands, or magnetic nanoparticles. The charge and magnetic interaction between neighbouring QCA devices enables the transmission and processing of information.

Super capacitors

Supercapacitors are electrochemical capacitors that take advantage of the double-layer charge that forms across electrode-solution interfaces. By maximizing the internal surface area available, while minimizing the weight, it is possible to achieve very high specific capacitances. Energy storage density can be further increased by coating porous electrodes with redox active materials that store charges within their volumes.

Vacuum nano-electronics

The mobility of electrons moving in vacuum does not suffer from the scattering events that are present inside matter. As a result, electronic transport can be very fast in vacuum, making ultra-fast operation possible. Nanoscale devices where the conducting channel is in vacuum are thus becoming more and more attractive as we search for new technologies to make devices working in the THz regime. Highly controllable nanoscale electron emitters are being investigated to make vacuum nano-electronic devices possible.

Research Projects include:


Study of the Near-Surface Stress around Cu-filled and CNT-filled through silicon vias
Near-surface Stresses in Silicon around Cu-filled and CNT-filled Through Silicon Vias
The demand for multifunctional and high-performance integrated circuits and systems has necessiated three-dimensional (3D) integration with through silicon via (TSV) technology. The thermomechanical stress originating from the mismatch in the coefficient of thermal expansion of Cu and silicon is a serious concern on mechanical reliability and electrical variability.
The thermomechanical stress originating from the mismatch in the coefficient of thermal expansion of Cu and silicon is a serious concern on mechanical reliability and electrical variability. This project investigates the stress distribution dependence on TSVs diameters and operation temperatures using micro-Raman and COMSOL simulations, and the impact on the keep-out-zone.
Plants capture photons very efficiently. Can we learn from them in making photovoltaic devices? We are investigating the use of photosynthetic protein complexes in solar cells, with the aim of creating very low cost solar cells.
The countless number of applications urged a demand for high performance micro-accelerometers, which in turn continue to gain momentum. Within that framework, one must justify the need for an approach defined by a system level performance in closed loop integration, by understanding the current performance limitations in the state-of-the-art micro-accelerometers, in research, on the market, and when employed with other electrical components.
Gyroscopes are used to sense angular rate and when used along with accelerometers can be used as effective navigation sensors. Due to their tiny size(1cmx1cm)die and high sensitivity they could be used in minimally invasive surgery.
Modal Analysis
A significant challenge in research on nanostructures is the lack of sufficient control over the fabrication processes. Therefore, an important aspect of our research is the study of nanostructure fabrication processes with the goal of achieving higher levels of control and reproducibility.
When electrons are confined in one or more dimensions, their wave nature and quantum mechanical effects become very apparent. Devices such as quantum wires and quantum dots operate based on this principle. We work on fabricating such devices by exploiting the inherent properties of nanotubes and nanowires.
In nanoscale optical devices, both the particle and the wave nature of light can play important roles. This creates new opportunities for engineering the optoelectronic properties, for instance the amount of light absorption in a device.
Nanoscale devices where the conducting channel is in vacuum are becoming more and more attractive as we search for new technologies to make devices working in the THz regime. We are investigating highly controllable nanoscale electron emitters to enable vacuum nano-electronic devices.
We use techniques ranging from classical, continuum modeling, to molecular dynamics, to quantum mechanical simulations using the density functional theory and first-principles techniques such as the Hartree-Fock method. We investigate the mechanical properties, electronic structure, transport characteristics and optical properties of nanodevices.
Molecular Quantum Cellular Automata (QCA), is an exploratory computing paradigm in which information is encoded in the electronic charge configuration of a QCA cell (built from one or two individual molecules). The charge interaction between neighbouring cells enables the transmission and processing of information. Our research focus is on the design and simulation of QCA using numerical tools such as the QCADesigner tool developed in our lab.
QCA processor designed using QCADesigner
We are studying the properties of carbon nanotube (CNT) biosensors using numerical simulation. The research is focusing on the electronic transport through CNTs that are exposed to various amino acids and short peptides. Using a combination of molecular dynamics, density functional theory, and quantum transport calculations we are able to predict how the adsorption of these peptides affects the transport through the tubes.
CMUT arrays promise a new generation of ultrasound imaging systems, with applications in 3D and 4D (real-time 3D) non-invasive imaging or high-frequency imaging (ultrasound biomicroscopy). The project targets the development of a portable CMUT-based ultrasound imaging system, to be used for breast cancer detection and monitoring.
The objective of this project is to build an adaptive micro-optical systems using a 2D micromirror array adaptively controlled through digital signal processing algorithms implemented in reconfigurable hardware (FPGA)
Compared to other patterning techniques, inkjet printing provides a very versatile and low cost microfabrication capability that can be used to implement organic electronic devices including printable sensors, transistors, LEDs, and photovoltaics. Inkjet technology can be used to pattern a variety of liquids including polymers, proteins, and various solvents. Inkjet patterns can be made on a variety of substrates and in 3D.
Application of printing methods in producing organic transistors has promised low-cost electronics, but a printed transistor has a poor performance due to the thick semiconductor layer. Also, most of organic transistors operate at high voltages (> 40V). We are investigating two types of organic transistors, OMESFET and dual gate transistor, to overcome the voltage problem and enhance the performance in a thick film transistor.
By embedding low dimensional (0D, 1D, 2D) materials such as nanowires, nanotubes and quantum dots in polymers, we want improve the conversion efficiency and extend the use of solar energy, as a viable clean energy solution. Significant improvements in photocurrent and photoabsorption of polymers doped with carbon nanotubes are promising for nanocomposite solar cells.