GaN Nanowires for MEMS and Optoelectronic Applications
PIs: Victor M. Bright, Kris Bertness (NIST)
Students: Matt Brubaker
Project field/specialty: GaN Nanowires, Selective Epitaxial Growth
Project Description:
GaN nanowires have several unique characteristics that make them attractive for MEMS and optoelectronic applications. The nanowires can be grown defect free due to their ability to accommodate higher levels of strain and to allow migration of dislocations to the wire surface. As a result the nanowires exhibit high performance electrical, optical, and mechanical properties that have enabled implementation in a wide variety of devices. By comparison, thin film GaN typically has many dislocations that result from lattice mismatch to the substrate and result in degradation of optical and electronic properties.
Currently many devices are fabricated by ultrasonically harvesting GaN nanowires and dispersing via suspended solution onto the device substrate, yet it is desirable to develop a method by which the wires are intentionally grown in their intended locations. While the as-grown nanowires exhibit a high degree of crystallographic orientation relative to the substrate, the lateral growth location is random and the wires bear some resemblance to a Lodgepole Pine forest. The goal of this research project will be to continue development of fabrication processes and strategies for selective epitaxial growth for site-specific deposition of nanowires. This would yield greater flexibility in device design and provide a potentially higher yield manufacturing route.
Figure: Magnesium doped GaN nanowires grown by Plasma Enhanced MBE
Reference: K.A. Bertness, A. Roshko, L.M. Mansfield, T.E. Harvey, N.A. Sanford, Journal of Crystal Growth, 310 (2008), pp. 3154–3158
Funding Source: NIST
