# Presentation: 467709

## The arrangement of carbon (C) atoms differentiates a pencil lead from a pricey diamond. In this project we investigate how to control the arrangement of boron (B), carbon (C) , and nitrogen (N) atoms for the formation of frontier carbon materials: boron nitride (B-N), carbon nitride (C-N) and boron-carbon nitride (B-C-N) phases. 

- Boron nitride nanotubes (BNNTs) are among the prospective materials for nanotechnlogy. They possess uniform electronic properties that are insensitive to their diameters and chiralities. This makes BNNTs very attractive for nanoelectronic and optoelectronic devices with predictable performance. Their band gaps are tuneable and can even be eliminated by transverse electric fields. This tunable property will trigger other innovative applications in the areas of nanoscale science and technology. However, high growth temperatures (>1100 oC), low production yield, and impurities have prevented effective synthesis and applications of BNNTs in the past ten years. For the first time,  we show that BNNTs can be grown on substrates at 600 oC. These BNNTs are grown vertically aligned on desired locations and patterns on the substrates (a). They can be used for applications without purification. Transmission electron microscopy indicates that the BNNTs are constructed of high-order tubular structures.
- A phase selective growth mechanism is demonstrated in this work. As shown, (b) low energy species will be coated as B-N films. Energetic species (c) will bounce away and prevent the coating of B-N films. Highly energetic species will react with the iron nanoparticles and form BNNTs (d & e). We anticipate that this mechanism can transform other thin film materials into nanostructures. This approach may also lead to the discovery of new nanophase materials.

**Notes:**
This is the first success of growing BNNTs on substrates. The growth temperatures are about half of those required for all other know techniques. These BNNTs are grown vertically aligned on desired locations and patterns. We anticipate that this is the starting point for doping and even making hetero-junctions of BNNTs and carbon nanotubes on substrates. The phase selective growth mechanism defined here could lead to the discovery of new metastable materials. This work will be published in Nano Letters.

## Slide 2

**Notes:**
We aim to stimulate the interest of the younger generations on science and technology.
This year, our open house was conducted on 9/17/05. 
The Summer Youth Program was conducted together with Prof. Paul Bergstrom and Prof. Craig Friedrich (7/18/2005 to 7/23/2005). 
This year, 3 students were trained for summer research and two of them were supported/cost shared by the NSF project. 
The Engineering Explorations are 2-hour programs for Engineering freshmen at Michigan Tech. 
There were 10 students from 5 departments attended the new graduate course.
PH1160 is officially a Honors Physics I Mechanics course. Part of the course is devoted to know the “hot topics” in physics and professional opportunities. Students will have seminars from some faculty in the department. Prof. Raymond Shaw is the instructor of this course.