InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal structures

Abstract

Electrical operation of InGaN/GaN quantum-well heterostructure photonic crystal light-emitting diodes (PXLEDs) is demonstrated. A triangular lattice photonic crystal is formed by dry etching into the top GaN layer. Light absorption from the metal contact is minimized because the top GaN layers are engineered to provide lateral current spreading, allowing carrier recombination proximal to the photonic crystal yet displaced from the metal contact. The chosen lattice spacing for the photonic crystal causes Bragg scattering of guided modes out of the LED, increasing the extraction efficiency. The far-field radiation patterns of the PXLEDs are heavily modified and display increased radiance, up to ∼1.5 times brighter compared to similar LEDs without the photonic crystal.

Thin-film silicon solar cells with efficient periodic light trapping texture

“…The interaction principle of light waves incident on a surface with a nanostructure in the wavelength range 1 is a key question in the development of optical technologies, such as solar cells, 2 light-emitting diodes, 3 photonic crystals, 4 and surface plasmon metal devices. 5 Efficient thinfilm solar cells based on microcrystalline silicon ͑ c-Si: H͒ or amorphous silicon ͑a-Si: H͒ with an absorber layer in the micrometer range require effective light trapping and an optimal incoupling of the entire sun spectrum.…”

Ga N ∕ In Ga N light emitting diodes with embedded photonic crystal obtained by lateral epitaxial overgrowth

“…[3][4][5][6][7][8] However, harnessing the full potential of PhCs has proved difficult: the largest light extraction enhancements reported in the literature are approximately twice, which are largely below theoretical expectations. Indeed, efficient PhCs require full optimization of the design, 9 including choices of the crystal lattice 6 and of the vertical structure.…”

Surface plasmon enhanced spontaneous emission rate of InGaN∕GaN quantum wells probed by time-resolved photoluminescence spectroscopy

“…There are only a few reports on the enhancement of the emission rates by reducing the piezo-electric field 20 and making photonic crystal structure. 21 We believe that our developed SP coupling technique has the potential to enhance the spontaneous emission rate dramatically. 4 Since the density of states of SP mode is much larger, the QW-SP coupling rate should be very fast, and this new path of a recombination can increase the spontaneous emission rate.…”