Ion Beam Fabrication and Modification of Nanoscale Structures and Devices with In Situ Feedback Control

Harvard University, Cambridge MA

Investigators

Abstract

This experimental condensed matter physics project focuses on the development of ion beam processing techniques to fabricate nanoscale structures in a controlled way. Nanoscale atomic scale flows of material will controlled by exposure to MeV heavy ion bombardment. New feedback controlled ion bombardment methods are used to control the size of nanopores in silicon nitride. The detailed atomic scale mechanism responsible for the observed modification of these nanopores is not understood and is an objective of this project. The tunneling based feedback control concept will be generalized to surface structures being exposed to high-energy ion fluxes. A goal is to fabricate lateral nanoscale electronic devices like tunnel junctions and room temperature single electron transistors. A potential application would be to electronically read DNA base sequences of a single molecule at kilo to megabase/second as the molecule moves through a nanopore structure. The project will train graduate students and postdoctoral fellows in the art and science of nanofabrication. These cutting-edge skills will prepare the participants for modern careers in industry, academe, and government. %%% This condensed matter physics project will study of the influence of energetic ion beams on the atomic scale structure of materials. Of interest are fundamental processes responsible for ion beam induced motions of atoms of an exposed material. Control over these motions can ultimately be used to fabricate electronic and mechanical devices of unprecedented small size and sensitivity. This could lead to fabrication of extremely small and sensitive electronic devices, capable of amplification, computation, or chemical sensing on the atomic scale. An exciting example of the latter would be a "DNA Transistor", capable of electronically reading the sequence of a single DNA molecule on a very short time scale. This will require the ability to fabricate solid state structures with articulated features on the length scale of 15 Angstroms. This research program will provide training of graduate students and postdoctoral fellows in an important area of nanoscience and technology, prepare them for careers in industry, government, and academe.