Top-down fabrication of horizontally-aligned gallium nitride nanowire arrays for sensor development

This paper demonstrates a high-throughput fabrication method of gallium nitride (GaN) nanowire (NW) and sub-micron wire (SMW) arrays using a combination of projection lithography, plasma etching, and post-plasma wet etching techniques. Photoluminescence (PL), field emission scanning electron microscopy (FFSEM), and I-V measurements were used to characterize the GaN NW/SMW devices. These NWs/SMWs can be used to create highly-sensitive and selective conductometric chemical/bio-sensors. The length and width of the wires can be precisely customized. The length of the NW/SMW varied from 5 pm to. 5 mm and the width ranges from 100 nm to 500 nm. Such comprehensive control in the geometry of a wire is difficult to achieve with other fabrication methods. The post-plasma KOH wet etching greatly reduces the surface roughness of the GaN NW/SM as well as the performance of devices. Complementary metal-oxide-semiconductor (CMOS) and micro-electro-mechanical system (MEMS) devices can be incorporated with GaN NW/SMW arrays on a single chip using this top-down fabrication method. (C) 2015 Elsevier B.V. All rights reserved.