Nitride Semiconductor Nanocones for Light Extraction
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Solution Overview
Problem
Conventional nitride light emitting diodes suffer from low light extraction efficiency due to total reflection of light at the interface between the nitride semiconductor material and the outside environment, limiting their brightness and suitability for modern electronic products that require miniaturization and reduced weight.
Innovation Solution
The formation of nanocones on the surface of the nitride semiconductor layer during the growth of the thin nitride film, which reduces the amount of light reflected back into the diode and enhances light extraction efficiency without the need for additional etching processes, thereby simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional nitride light emitting diode structure is used, then manufacturing process is simple, but light extraction efficiency is low due to total reflection at the interface
Solution Approach 1:
The patent applies curvature by forming nanocones with curved surfaces on the light emitting surface of the nitride semiconductor layer. These curved nanocone structures replace the conventional flat surface, enabling light to escape at multiple angles and reducing total internal reflection. The curvature of the nanocone surfaces allows light rays that would otherwise be reflected back into the semiconductor to be redirected outward, significantly improving light extraction efficiency without complicating the manufacturing process.
Solution Approach 2:
The patent transitions from a two-dimensional flat light emitting surface to a three-dimensional nanocone structure array. By adding the vertical dimension and creating conical protrusions, the effective light extraction area is increased and light can escape through multiple spatial directions. This dimensional transformation allows light to be extracted not only horizontally but also at various angles along the nanocone surfaces, overcoming the limitation of total internal reflection in conventional planar structures.
2Illumination intensity
If light extraction efficiency is improved by conventional methods (electrode design, package structure), then brightness increases, but device complexity increases
Solution Approach 1:
The patent applies local quality by modifying only the local surface properties at the light emitting interface through nanocone formation, rather than changing the overall electrode design or package structure. The nanocones are formed locally on the light emitting surface of the nitride semiconductor layer, creating localized regions of enhanced light extraction. This localized modification achieves brightness improvement without requiring complex changes to the entire device architecture, maintaining simplicity in electrode design and package structure.
Solution Approach 2:
The patent replaces mechanical/structural modifications (complex electrode designs, package structures) with a surface morphology modification approach. Instead of mechanically redesigning electrodes or packages to improve light extraction, the invention uses epitaxial growth to create nanocone surface structures that optically enhance light extraction through their geometric properties. This substitution of structural complexity with surface geometry simplifies the overall device design while achieving the desired brightness improvement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves light extraction efficiency by reducing the amount of light lost to total reflection, increasing the brightness of the light emitting diode and enabling more compact, lightweight designs.
Implementation Method 1
a light emitting diode (LED) is a kind of semiconductor device that converts electricity into light using the characteristics of a compound semiconductor
Implementation Method 2
Conventional nitride light emitting diodes suffer from low light extraction efficiency due to total reflection of light at the interface between the nitride semiconductor material and the outside environment
Implementation Method 3
a plurality of nanocones formed at the surface thereof by epitaxial growth
Data Source
AI summary
A light emitting device is disclosed. The light emitting device includes a conductive support layer; a reflective layer disposed on the conductive support layer; a nitride semiconductor layer disposed on the reflective layer. Furthermore, the nitride semiconductor layer includes a second-type semiconductor layer on the reflective layer, an active layer on the second-type semiconductor layer, and a first-type semiconductor layer on the active layer; a light extraction structure disposed on the first-type semiconductor layer; and a first-type electrode disposed on the light extraction structure.