Improved optical properties using self-organized GaN nanotip structure

A self-organized GaN nanotip structure, which was a nanoscale tip-shaped pillar, was fabricated on a GaN surface by reactive ion etching (RIE) using chlorine plasma. The nanotip structure with periods smaller than the wavelength of light can provide antireflection and enhanced transmission effects from the ultraviolet (UV) to the visible region (300 nm ∼ 900 nm). We have found that the height and the density of the nanotip structure can be controlled from 0.1 μm to 2.0 μm and from 109 cm−2 to 1011 cm−2 by changing etching conditions, respectively. The nanotip structure with controlled height and density exhibited the drastic improvement of the transmission property in the UV region compared with what is conventionally fabricated. These excellent optical properties of the nanotip structure are expected to improve the performances of light-emitting and photo-detective devices. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)