Boron phosphide (BP) is a lightweight, hard, thermally stable, corrosion resistant compound with a wide indirect band gap and high-electron mobility. These properties make it ideal for use in semiconductors, optoelectronics, thermo-electronics, and even smoke grenades. BP is one of the few environmentally benign sources of phosphorus which maintains its demand.
Many of the methods utilized for producing BP require complex steps using toxic materials or high levels of energy input to drive the synthesis reaction. Typically, a precursor mixture is heated in a sealed tube to a very high temperature or dropped directly into a superheated reaction zone in excess of 1000° C. These approaches have been adopted reasonably well in the laboratory as a chemical vapor deposition (CVD) process to grow BP epitaxial layers on various supporting substrates, but the use of highly toxic and flammable reagents at high temperatures presents a significant challenge for any of these processes to be implemented safely and economically in a large-scale operation.
Army researchers have developed a high-yield process to synthesize BP where boron phosphate and magnesium metal are combined into a homogenous mixture without the need for temperature-controlling diluents, loosely packing the mixture at a pressure of 0 to 20,000 psi, and igniting the mixture using minimum energy input to create a self-propagating high-temperature synthesis reaction that produces BP.
- Cheaper, safer, and more environmentally friendly than current synthesis methods
- Reaction between boron phosphate and magnesium metal particles is initiated with a limited amount of energy input and sustained by its own heat output
- Process can be easily implemented with any known art of material processing
- No need for diluents
- US patent 9,790,093 available for license
- Potential for collaboration with Army researchers