A nanoporous AlN layer patterned by anodic aluminum oxide and its application as a buffer layer in a GaN-based light-emitting diode

Abstract

This work investigates a nanoporous aluminum nitride (AlN) layer prepared using an anodic aluminum oxide (AAO) process and its application as a buffer layer for a GaN-based light-emitting diode (LED) fabricated on sapphire substrate. Following this AAO process, the average pore spacing and pore diameter of the nanoporous AlN layer were in the ranges 180-200 nm and 100-150 nm, respectively. The light output power of the GaN-based LED with a nanoporous AlN layer was about 53% higher than that of a GaN-based LED without a nanoporous AlN layer at an injection current of 20 mA. At an injection current of 80 mA, the light output power was increased by about 34%.

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

“…To increase the internal quantum efficiency and light extraction efficiency of GaN-based LEDs, they are fabricated on a patterned sapphire substrate (PSS) [3-6]. Air gaps between GaN and the sapphire substrate can be formed by geometrically patterning the substrate to release the internal stress that is associated with the lattice mismatch that exists at the air gap, reducing the dislocation density and improving the quality of the film.…”

Antireflection characteristics of inverted nanopyramid arrays fabricated by low-cost nanosphere lithography technology

“…However, more than 35% of incident light is reflected back from silicon (Si) surfaces by Fresnel reflection because of the large refractive index discontinuity at the interface of Si and air. To suppress the Fresnel reflection, ARCs directly patterned on Si substrates have been extensively explored both experimentally [1][2][3][4] and theoretically, [5][6][7] and various randomly or periodically structured surfaces, including upright or inverted pyramids, 1,2,9,10 nanopillars, [11][12][13][14][15] nanowires/nanocones, 3,16,17 and porous structures 18 have been reported. However, the controllable, low-cost, and efficient fabrication of such nanostructures still remains a problem.…”

Oblique-angle sputtered AlN nanocolumnar layer as a buffer layer in GaN-based LED

“…The anisotropic nature of these nanocolumnar films suggests their feasible application of nanocolumnar films in optical, chemical, biological, mechanical, magnetic, and electrical devices [21]. As is well known, aluminum nitride (AlN) functions as an intermediate layer that can improve the quality of GaN epitaxial layers that are grown on sapphires or other substrates [22][23][24]. Therefore, this work studies an AlN nanocolumnar buffer layer that is prepared by OAD.…”