Vortex fluidic exfoliation of graphite and boron nitride.
This proposal was received in response to the Nanoscale Science and Engineering Initiative, Program Solicitation NSF 01-157, in the NER category. The primary objective of this research is to develop a fundamental understanding for synthesizing/manufacturing boron nitride nanotubes (BN-NTs) predictably and reproducibly by Electron Cyclotron Resonance Microwave Plasma Chemical Vapor Deposition (ECR-MPCVD). Pure BN nanotubes present an attractive opportunity for practical applications. They offer a unique combination of electrical and mechanical properties. Their predicted wide band-gap is independent of tube structure, which reveals BN-NTs potential for new generations of nanoelectronic devices based on field emission and cold cathode characteristics. This exploratory NER project will use ECR-MPECVD to synthesize BN-NTs. The unique features of this study will be to select novel metal-organic precursors, incorporate appropriate catalysts, and provide special surface pre-treatments to enhance formation and growth of single and multi-walled BN-NTs. In addition, in situ monitoring of plasma chemistry and processing parameters will be performed to relate to BN-NTs formation and growth. The proposed research will investigate two unique aspects: (1) Roles of the precursor chemistry on the synthesis of BN-NTs, and (2) Effects of substrate pretreatment such as surface modification by seeding and ion implantation on the BN-NTs formation and growth. In addition, influence of special catalysts such as Li3N and Mg3N2 on the synthesis of BN-NTs will be investigated. HRTEM, EELS, SEM, TED and possibly other analytical techniques will characterize the nanotubes. In addition, selected electrical properties of BN-NTs will be measured for applications in electronics.
On a broader scale, a successful completion of this research will lead to a knowledge base for synthesizing BN-NTs with exceptional electrical, thermal, and mechanical properties for applications in electronics. It is expected that future generations of nanostructure electronic devices can be based on BN-NTs. For example, BN-NTs may serve as a perfect nano-insulating tubular shield for any conducting material encapsulated within. This offers the possibility of nanotube electrical transport tailored over a wide range. Unique field emission and cold cathode characteristics of BN-NTs have applications in flat panel display devices. Another important goal of this project is to train graduate student and research associate/post doc through participation on this research project and their MS and Ph.D. theses. In addition, minority/women high school and undergraduate students will also be mentored and exposed to this research.