LED with Oxidized Metal Contacts for Light Extraction
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Solution Overview
Problem
Current light emitting diodes (LEDs) used in electronic displays, such as backlights in laptops or televisions, face challenges in achieving efficient multicolor emission without the need for multiple substrates or complex stacking, and in providing high light extraction efficiency and color gamut coverage.
Innovation Solution
The development of nanowire-based light emitting diodes with oxidized metal contacts, including a first conductivity type semiconductor material region, an active region, a second conductivity type semiconductor material layer, a nickel or gold layer, and a transparent conductive layer formed by oxidizing the metal layer stack, along with a reflector layer, enables efficient light emission across multiple colors on a single substrate, enhancing light extraction and color representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional LED structures are used with metal contacts, then electrical conductivity is achieved, but light extraction efficiency is reduced due to metal absorption and reflection
Solution Approach 1:
The patent changes the physical and chemical state of the contact layer by oxidizing metal layers (nickel, gold, or copper) to form transparent conductive metal oxides. This parameter change transforms the contact from a reflective metal surface to a transparent conductive oxide layer, allowing light to pass through while maintaining electrical conductivity, thereby resolving the contradiction between electrical conductivity and light extraction efficiency
Solution Approach 2:
The patent converts the harmful effect of metal contacts (light absorption and reflection) into a beneficial transparent conductive contact. By oxidizing the metal layers, the harmful reflective properties are transformed into useful transparent conductive properties, turning the previously harmful metal-contact-light interaction into a beneficial transparent contact that maintains both conductivity and optical transparency
2Illumination intensity
If multiple substrates or complex stacking are used to achieve multicolor emission, then color gamut coverage is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple LED structures onto a single substrate, integrating red, green, and blue emitting regions in one device. This consolidation eliminates the need for multiple separate substrates or complex stacking arrangements, achieving full color gamut coverage while reducing overall device complexity and enabling direct view display applications
Solution Approach 2:
The patent creates a universal LED structure that can emit multiple colors (red, green, and blue) from a single device. This multi-functional LED replaces the need for separate single-color LEDs or complex stacking arrangements, providing full color capability while simplifying the overall display structure and enabling direct view display functionality
3Reliability
If metal layers are used for electrical contacts, then electrical conductivity is maintained, but transparency is reduced
Solution Approach 1:
The patent changes the material parameters by transforming metals into their oxidized forms (metal oxides). This parameter change results in materials that simultaneously possess both electrical conductivity and optical transparency, resolving the contradiction between maintaining electrical conductivity and achieving optical transparency in contact layers
Solution Approach 2:
The patent employs composite material structures consisting of metal layers oxidized to form transparent conductive metal oxides. These composite materials combine the electrical conductivity characteristics of metals with the optical transparency of oxides, achieving both required properties simultaneously in the contact layer
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 allows for the creation of direct view display devices with improved light emission efficiency and color gamut coverage, eliminating the need for backlight units and liquid crystal materials, while enabling the formation of multicolor pixels with red, green, and blue subpixels on a single substrate, enhancing display vibrancy and efficiency.
Implementation Method 1
oxidizing the metal layer stack to form a transparent conductive layer including at least one conductive metal oxide
Implementation Method 2
diffusing the gold layer into the second conductivity type semiconductor material layer through the nickel layer during the step of oxidizing to form a gold doped semiconductor region
Implementation Method 3
nanowire-based light emitting diodes with oxidized metal contacts
Implementation Method 4
enables efficient light emission across multiple colors on a single substrate
Implementation Method 5
a reflector layer located on the transparent conductive layer
Data Source
AI summary
A light emitting diode includes a first conductivity type semiconductor material region, an active region located over the first conductivity type semiconductor material region, a second conductivity type semiconductor material layer located over the active region, a first layer containing at least one of nickel or gold located over the second conductivity type semiconductor material layer, a reflective top contact electrode located over the first layer, a dielectric material layer located over the top contact electrode and containing an opening, and a reflector located over the dielectric material layer and contacting the top contact electrode through the opening in the dielectric material layer.