Properties of GaN-based light-emitting diodes on patterned sapphire substrate coated with silver nanoparticles prepared by mask-free chemical etching

Abstract

This study reports on the use of a template that is made of silver nanoparticles (ANPs) that are dispersed on a patterned sapphire substrate (PSS) to improve the light output power of GaN-based light-emitting diodes (LEDs). The dipping of a sapphire substrate in hot H2SO4 solution generates white reaction products that are identified as a mixture of polycrystalline aluminum sulfates. These white reaction products can act as a natural etching mask in the preparation of an ANP-coated PSS (PSS-ANP) template. The optimal annealing temperature and time, surface morphology, and optical characteristics of the PSS-ANP template were investigated. The light output power of an LED that is bonded to the PSS-ANP template is approximately double than that of an LED that is not.

Band offsets of non-polar A-plane GaN/AlN and AlN/GaN heterostructures measured by X-ray photoemission spectroscopy

“…During the last decade, group III-V nitrides are very promising semiconductor materials for application in high frequency heterojunction field-effect transistors (HFETs) [ 1 - 8 ]. Large band offsets at the heterojunctions are important to realize these device applications.…”

Nanostructure analysis of InGaN/GaN quantum wells based on semi-polar-faced GaN nanorods

“…To improve the quality of InGaN epitaxy grown on sapphire substrate and to solve lattice structure mismatch between the sapphire substrate and GaN, researchers have developed epitaxy techniques, such as epitaxial lateral overgrow [6], micro-level SiNx with patterned SiNx interlayer structures, and patterned sapphire substrates [7,8]. Research efforts related to growing GaN on non-polarized sapphire substrates have gained considerable attention in recent years, especially because of the results reported by S. Nakamura and his team [9][10][11].…”

Silane controlled three dimensional GaN growth and recovery stages on a cone-shape nanoscale patterned sapphire substrate by MOCVD

“…Both the crystalline quality and the light extraction efficiency (LEE) of LEDs can be improved significantly. 2,3 A trend with PSS technology is to shrink the pattern size to get more light extraction [4][5][6][7] and to resolve the wafer bowing problems in GaN growth on large size sapphire substrates (more than 4 inch) 8,9 and in thick film growth, such as 300 μm or more on a heterogeneous substrate. 10 Nano PSS (NPSS) have been paid much attention for the fabrication of high efficiency LEDs in recent years.…”