Determining the electronic performance limitations in top-down-fabricated Si nanowires with mean widths down to 4 nm.

Silicon nanowires have been patterned with mean widths down to 4 nm using top-down lithography and dry etching. Performance-limiting scattering processes have been measured directly which provide new insight into the electronic conduction mechanisms within the nanowires. Results demonstrate a transition from 3-dimensional (3D) to 2D and then 1D as the nanowire mean widths are reduced from 12 to 4 nm.

Multi-wavelength filters in silicon using superposition sidewall Bragg grating devices.

Multiple-filter stopbands, with the potential to be nonuniformly spaced in frequency, are realized in a single integrated Bragg grating device on silicon. By utilizing a superposition of sidewall relief grating functions, N individual filter responses can be fabricated with a device length N× shorter than the equivalent serial set of gratings. Arbitrary combinations of eight-basis filter responses were demonstrated as selected by an eight-bit pseudorandom number generator, showing the flexibility of the complex Bragg grating device design.

Emission characteristics of photonic crystal light-emitting diodes.

Experimentally measured optical properties of photonic crystal LEDs are reported here. Photonic crystal and photonic quasi-crystal structures were fabricated on GaN epilayer LED wafer material using both direct-write electron beam lithography and nanoimprint lithography. Some of these structures were processed to make finished LEDs.