Current projects
Science Foundation Ireland (SFI) Principal Investigator:
Studies of planar nanowire arrays as basis for new generations of ICT devices
This project proposes to develop new techniques for the formation of nanowire arrays at the extreme of the nanowire cross-section dimensions and separation, down to 4 nm. This is the range which cannot be explored by a conventional “top-down” lithography approach. The initial aim it to fabricate coherent, well ordered planar nanowire arrays and furthermore to have the flexibility to vary the materials of the nanowires and substrate.
We aim to demonstrate the deposition of nanowires of magnetic materials and semiconductor materials by essentially the same fabrication process, thus proving its universal value.
Two rather different ranges of phenomena will be studied in these arrays. In the case of the magnetic nanowires we aim to study the spin-dependent electron transport across the nanowires. We aim to demonstrate that a new class of magnetic domain walls can be nano-engineered, leading to a large increase in the value of magneto resistance in the array. In the case of the semiconductor nanowires we aim to study the mechanism of the electron mobility in the nanowires to establish if current confinement can lead to an increase in the mobility through quantum effects or strain stored in the nanowire.
Two demonstration devices shall be investigated. They are not by-products of the project but rather essential elements of it. For example of one the devices, the field-effect transistor, shall be required to measure the mobility of the current carriers.
The project comprises internationally renowned groups form Ireland, Germany and the USA.
Science Foundation Ireland (SFI) Industrial Supplement:
Studies of the current induced magnetisation dynamics in nanowire arrays
The main objective of the proposed Industry Partnership Industry Supplement is to investigate the Direct Current Driven Magnetisation Dynamics (DCDMD) in magnetic nano-scale elements. The magnetic elements will consist of planar arrays of magnetic nanowires grown by the Atomic Terrace Low Angle Shadowing (ATLAS) technique, with width down to 6-20 nm. The influence of the cross-sectional dimensions of the nanowires and the separation between them on the microwave resonance caused by dc current will be studied. The DCDMD regime will be investigated by measuring the microwave emission from the nanostructures using low-noise microwave preamplifier. The planar structure offers interesting options of creating magnetizations of “pinned “ layers (PL) and “free” layers (FL) in non-collinear states by utilizing shape anisotropy. This approach may have an advantage over other methods in terms of ensuring higher current spin polarization and therefore higher efficiency of a current driven magnetization process.
The project is conducted in collaboration with Seagate Technology LLC, the internationally reknowned magnetic memory device vendor.
European Framework Programme 7 (FP7) - ERANET NanoScience Europe
Nanowire based Microwave Emitters for Use in Monolithic Microwave Integrated Circuits
The scientific objective is to develop an understanding of the phase coherency and the mechanism of phase locking in arrays of nano-contacts in the process of spin polarised induced generation of microwaves by spin torque.We shall focus on the microwave oscillator and its dependency on the size and separation between individual nanocontacts.The nanocontacts shall be formed by intersection of an array of magnetic nanowires and cross-electrodes.We shall investigate the effect of the coherent coupling of microwave emissions from such arrays and determine the power enhancement as a factor of proximity between the neighbouring nanowires or between magnetic contacts positioned along the same nanowire. Project innovations are the self-assembly of arrays of nanocontacts using a deposition technique capable of forming planar arrays of nanowires and the geometry of magnetic nanocontacts that allows for experiments with large angle between magnetic moments of the two ferromagnetic layers.
Science Foundation Ireland (SFI) Technology and Innovation Development Award
Nano enabled transparent conductors
The scientific objective of this project is to investigate the feasibility of improving transparent conducting layers grown at low temperatures for use in flexible photovoltaic solar cells and other transparent electronics devices. It is expected that this project will pave the way towards more in-depth investigations of novel materials for use as transparent conducting oxide layers for use in flexible and convention photovoltaic solar cells. Eventually it is expected that the technology here developed will compete with existing, but very expensive, transparent conducting oxides such as indium tin oxide.