Highly linearly polarized white light emission from InGaN light-emitting diode with nanograting-integrated fluorescent ceramics

Abstract

We proposed and demonstrated a linearly polarized white light emission from an InGaN light-emitting diode with nanograting-integrated fluorescent ceramics. By incorporating a dielectric layer with low refractive index between multilayer nanogratings and a fluorescent ceramic, both high TM transmission (TMT) and high extinction ratio (ER) were effectively achieved across the entire range of white light. An ER higher than 20 dB and a TMT of 60% were obtained experimentally for a GaN/fluorescent-ceramic-integrated white LED with a multilayer grating of 150 nm period. The fluorescent-ceramic-integrated structure showed possibilities of implementing a polarized white LED with high performance.

Review—Recent Advances and Challenges in Indium Gallium Nitride (InxGa1-xN) Materials for Solid State Lighting

“…182,183 The In x Ga 1-x N LEDs can produce a linearly polarized light by incorporating a dielectric layer with low refractive index between the multilayer nanogratings and a fluorescent ceramic. 184 The nanowires of In x Ga 1-x N have exhibited exceptional optical properties by overcoming the drop in efficiency when the concentration of indium in the sample is increased. 51,185 The nanowires do have higher aspect ratios and the free sidewalls of the nanowires allows the elastic relaxation of strained axial insertions in contrast to planar structures where strain has to be relieved plastically above a critical composition thickness.…”

Magnetic-induced PL modulation of InGaN/GaN MQWs by a CoFeB ferromagnetic cap layer

“…Figure 3(a) shows the roomtemperature PL spectra of InGaN/GaN MQWs capped by ferromagnetic CoFeB layer. The incident excitation source is a 325 nm He-Cd laser vertically illuminating from the top side along [11][12][13][14][15][16][17][18][19][20]-axis orientation of InGaN/GaN MQW wafer. At the beginning of the PL measurements, its polarization direction is rotated in a-plane to maximize the emitted PL signal, in order to achieve the most efficient absorption of the excitation laser.…”

“…12) So a polishing process and special packages are necessary for c-plane LEDs to achieve high-quality polarized light. In addition, novel nanostructures for c-plane LEDs have been utilized to generate polarized emission by introducing the geometric anisotropy, such as photonic crystals, [13][14][15] asymmetric elliptical nanorods, 16,17) subwavelength nanograting, [18][19][20][21] surface plasmons, [22][23][24] metallic nanoparticles, 25) quantum dots in nanowire, [26][27][28] and dielectric/metal multilayer composite structures. 29,30) However, all these approaches are high-cost and inefficient because of the requirement of precisely nanostructure design and complicated fabrication.…”

Using chiral ammonium cations to modulate the structure of 1D hybrid lead bromide perovskites for linearly polarized broadband light emission at room temperature

“…47 For all enantiomers of the BuA-based compound, polarization-resolved PL emission measurements evidence a significant linear polarization at RT as the consequence of the structural anisotropy of the 1D crystal structure. Broadband polarized light sources are highly in demand for applications for display, imaging and optical communications devices 59 and the compounds described in this work expand the new family of polarized broadband light-emitting perovskite materials. Our results provide an example of how the structural distortions and the resulting photophysical properties can be driven by a targeted choice of the organic cations in lowdimensional HOIPs.…”