Tuesday, April 21, 2009

US Patent 7521274 - GaN nanowire LED fabrication using pulsed growth

US Patent 7521274

GaN is a semiconductor compound useful to the formation of LEDs for lighting and displays. Formation of GaN nanowires can enhance the density of electron states and improve the optical efficiency of LED or other optoelectronic devices however fabrication methods have been based on the vapor-liquid -solid method requiring catalytic material with limited control of uniformity and position of the nanowire growth. This patent from the University of New Mexico teaches an alternative approach based on the formation of patterned apertures servng as a template for the growth of a vertical array of GaN nanowires. Claim 1 reads:

1. A method of making nanowires comprising:

forming a selective growth mask over a substrate, wherein the selective growth mask comprises a plurality of patterned apertures that expose a plurality of portions of the substrate;

using a selective non-pulsed growth mode to grow a semiconductor material on each of the plurality of portions of the substrate exposed in each of the patterned apertures;

performing a growth-mode transition from the non-pulsed growth mode to a pulsed growth mode; and

forming a plurality of semiconductor nanowires by continuing the pulsed growth mode of the semiconductor material.