Realization of reliable GaN nanowire transistors utilizing dielectrophoretic alignment technique

Abstract

We have utilized dielectrophoretic force for assembling long ͑50 m to 200 m͒ GaN nanowires for device fabrication. These catalyst-free nanowires were grown by direct reaction of NH 3 and Ga, which resulted in free-standing nanowires along with GaN microplatelets. GaN nanowires were suspended in a solvent using sonication, and using dielectrophoretic forces nanowires were assembled on prepatterned substrates ͑SiO 2 coated Si and sapphire͒. With fabrication sequence using batch fabrication processes such as standard photolithography, etching, and oxide deposition we were able to realize stable GaN nanowire devices. The present technique is potentially compatible with complementary metal-oxide semicondoctor technology, and integrating nanodevices with conventional Si microelectronics on the same chip can be made possible with this technique. Utilizing this technique, high mobility ͑230 cm 2 V −1 s −1 ͒ GaN nanowire field effect transistors with reliable electrical characteristics have been achieved. These nanowire transistors even after prolonged period of conduction exhibited no deteriorations of their electrical properties. Several key factors in the processing that affect the device yield and reliability have been identified. Simple calculations predicted the effects of nanowire geometry, dispersing solvent, and alignment frequency on the dielectrophoretic force experienced by the nanowires.

Tensile measurement of single crystal gallium nitride nanowires on MEMS test stages

“…[1][2][3][4]. GaN nanowire cantilever resonators have been shown to have a high mechanical quality factor, which makes them appealing in nanomechanical devices.…”

Dielectrophoretic separation of carbon nanotubes and polystyrene microparticles

“…The distance between arrays was designed to be 260 lm to minimise the field interference between arrays. Similar designs have been extensively used in aligning and assembling of nanowires (Motayed et al 2006;Kim et al 2008;Lee et al 2008) for micro and nano electronics applications.…”

“…If damping and viscous forces are negated, the DEP force equation can be expressed as (Motayed et al 2006):…”

Recent Advances in Directed Assembly of Nanowires or Nanotubes

“…The alignment result depends on the electric voltage and frequency, as well as configurations and patterns of the electrodes. NWs have been assembled using DEP in high concentrations [59][60][61][62][63][64][65][66][67][68][69][70][71] or as individual entities [59][60][61][72][73][74]. For example, C. Chen [71] fabricated and integrated single-wall carbon nanotubes(SWCNTs) using DEP assembly, as shown in Fig.…”