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Nanoelectronics
Research Lab |
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Growth of
Germanium, Silicon Nanowires, and Heterostructures
Semiconductor nanowires offer a natural,
quasi-one dimensional test bed for electron physics in
reduced dimensions and as a platform for electronic devices. Core-shell
nanowires represent the quasi one-dimensional counterpart to the
two-dimensional quantum well. We are exploring the growth of band engineered
Ge-SiGe core-shell nanowires, in order to tailor their electronic properties,
and modulation doping as a method to reduce disorder and enhance the electron
mobility in this system.
High Performance Nanowire
Field-effect and Tunneling Field-effect Transistors
Owing to CMOS scaling issues, and in
particular to increased power dissipation in aggressively scaled transistors,
there is significant interest in devices that provide a lower dissipated
power at the same switching speed. Gate-all-around nanowire field-effect
transistors and tunneling field-effect are two device designs that can
provide a reduced operating power, thanks to better electrostatic control of
the channel. We are investigating the fabrication and
the electronic properties of germanium gate all around nanowire field-effect
transistors, and tunneling field-effect transistors. The devices are realized
using Ge-SiGe nanowire heterostructures and highly doped source and drain for
efficient electron injection.
(p-i-n Tunneling
Field-Effect transistor) Spin Injection in Germanium
Nanowires
There is growing interest in using the electron
spin degree of freedom for information processing, in addition to information
storage. Group IV semiconductors (e.g. silicon, germanium, graphene) are CMOS
compatible and have inversion symmetric crystal structures, a property that
suppresses spin-orbit interaction and enhances the spin relaxation time.
Using ferromagnetic electrodes and tunnel barriers, we are investigating the
electrical spin injection, detection and spin transport in germanium
nanowires. (GeNW spin injection device and
two-point magnetoresistance data) Electronic Transport in
Graphene Bilayers
When two layers of electrons are brought
in close proximity, new phenomena with no counterpart in the physics of the
single layer can emerge. A most
notable example is the electron-hole pairing and exciton condensation which
occurs at low temperatures in two closely coupled quantum wells. Using
transport techniques such as Coulomb drag and interlayer tunneling, we are
exploring electron-electron correlations and quantum coherence in two
graphene layers separated by an ultra thin dielectric.
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Last update 10/13/2011