Nano-patterned dual-layer ITO electrode of high brightness blue light emitting diodes using maskless wet etching

Abstract

We propose a dual-layer transparent Indium Tin Oxide (ITO) top electrode scheme and demonstrate the enhancement of the optical output power of GaN-based light emitting diodes (LEDs). The proposed dual-layer structure is composed of a layer with randomly distributed sphere-like nano-patterns obtained solely by a maskless wet etching process and a pre-annealed bottom layer to maintain current spreading of the electrode. It was observed that the surface morphologies and optoelectronic properties are dependent on etching duration. This electrode significantly improves the optical output power of GaN-based LEDs with an enhancement factor of 2.18 at 100 mA without degradation in electrical property when compared to a reference LED.

Foveated near-eye display using computational holography

“…The 3D scene is modelled as a set of luminous points, similar to methods where 3D objects are represented by point clouds 28 – 30 , and the hologram corresponding to the entire scene is generated by superposing the holograms for the individual points. The hologram for a single point is computed with an algorithm based on ray-tracing, which makes use of Zernike polynomials to estimate the wavefront exiting the SLM 31 – 33 .…”

Improvement in Light Output of Ultraviolet Light-Emitting Diodes with Patterned Double-Layer ITO by Laser Direct Writing

“…Moreover, compared to randomly distributed ITO pattern, the escape probability of photons emitting from the active region can be further increased by a regularly distributed ITO pattern [38]. However, patterned ITO has been shown to degrade the current spreading performance of UV LED due to an increase in sheet resistance [39,40,41]. Adding an annealed bottom ITO layer is an effective way to stabilize the current spreading and prevent electrical degradation.…”

Self-standing ZnO nanotube/SiO2 core–shell arrays for high photon extraction efficiency in III-nitride emitter

“…Many groups have tried to fabricate the ZNR arrays on emitters for enhancing photon extraction efficiency (PEE) of emitters by decreasing the difference of refractive index between GaN (n=2.4) and air (n=1) [9][10][11][12]. However, conventional GaN-based emitters use a indium tin oxide (ITO) layer (n=2.1) as a p-type transparent conducting electrode [13,14]. Therefore, a greater increase in the PEE of the emitter with ITO layer means that the refractive index of the ZnO nanostructures must be lower than the ITO layer.…”