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

• We disclose a top–down approach to the fabrication horizontal aligned single/multiple nanowire structure.
• We provide data on the quality of our nanowires.
• We present the UV response and possible applications (chemical/gas/biology sensors) of the nanowire array.

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 (FESEM), 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 μm 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/SMW 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.

In this paper, we describe a top–down method for the manufacture of horizontal aligned nanowire arrays for potential application to UV detector, chemical/gas/biology sensors. An illustration of the alignment-free nanowire is shown below:Figure optionsDownload as PowerPoint slideThis is a SEM image (× 600 magnification) of the longest total length (5000 μm) nanowire in serpentine shape. A total number of 81 NWs like this one are on a single die.