title: Nanotexturing of GaN light-emitting diode material through mask-less dry etching.
abstract: We describe a new technique for random surface texturing of a gallium nitride (GaN) light-emitting diode wafer through a mask-less dry etch process. This involves depositing a sub-monolayer film of silica nanospheres (typical diameter of 200 nm) and then subjecting the coated wafer to a dry etch process with enhanced physical bombardment. The silica spheres acting as nanotargets get sputtered and silica fragments are randomly deposited on the GaN epi-layer. Subsequently, the reactive component of the dry etch plasma etches through the exposed GaN surface. Silica fragments act as nanoparticles, locally masking the underlying GaN. The etch rate is much reduced at these sites and consequently a rough topography develops. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) inspections show that random topographic features at the scale of a few tens of nanometres are formed. Optical measurements using angle-resolved photoluminescence show that GaN light-emitting diode material thus roughened has the capability to extract more light from within the epilayers.
authors.affiliation: School of Engineering, University of Glasgow, Glasgow, UK.
authors.forename: Rafal
authors.initials: R
authors.lastname: Dylewicz
authors.forename: Ali Z
authors.initials: AZ
authors.lastname: Khokhar
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Wasielewski
authors.forename: Piotr
authors.initials: P
authors.lastname: Mazur
authors.forename: Faiz
authors.initials: F
authors.lastname: Rahman