Nanostructure Semiconductor Light-Emitting Device with Exposed Surface Area
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Solution Overview
Problem
Current semiconductor light-emitting devices with nanostructures face challenges in achieving high light extraction efficiency due to limitations in crystallinity and polarization-induced degradations, as well as inefficient light emission through a small surface area.
Innovation Solution
A nanostructure semiconductor light-emitting device is designed with a base layer, a material layer containing openings for light-emitting nanostructures, a filling layer that exposes portions of the nanostructures, and a conductive extension layer to enhance light extraction, along with a reflective metal layer and omnidirectional reflector to optimize light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light is emitted through a small surface area in conventional semiconductor light-emitting devices, then the device structure is simple, but light extraction efficiency is poor
Solution Approach 1:
The patent divides the light-emitting structure into multiple discrete light-emitting nanostructures (quantum dots) arranged in an array, rather than using a single continuous light-emitting layer. This segmentation increases the total exposed surface area for light emission while maintaining a manageable device structure through systematic arrangement of individual nanostructures.
Solution Approach 2:
The patent transitions from a planar light-emitting surface to a three-dimensional array of nanostructures with varying heights. By introducing vertical dimensionality and creating nanostructures of different heights (first height and second height), the device increases the exposed surface area for light extraction without significantly complicating the overall device footprint.
2Ease of manufacture
If active layers are obtained from polar surfaces in conventional devices, then the manufacturing process is simple, but crystallinity is poor and polarization-induced degradations occur
Solution Approach 1:
The patent changes the crystallographic orientation parameter of the semiconductor substrate from polar surfaces to nonpolar or semipolar surfaces. This parameter change in substrate orientation fundamentally improves the crystallinity of the grown quantum dots and eliminates polarization-induced performance degradations, while still allowing for controllable growth through adjusted deposition conditions.
3Device complexity
If all nanostructures are fully covered by filling layer, then the device structure is compact, but light extraction efficiency is reduced
Solution Approach 1:
The patent applies different filling layer heights to different regions, creating a height difference between filled and unfilled portions of nanostructures. Specifically, the filling layer covers the lower portion of each nanostructure while leaving the upper portion exposed. This local differentiation optimizes both structural support (from the filled portions) and light extraction efficiency (from the exposed upper portions).
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
The design significantly improves light extraction efficiency by increasing the exposed surface area of the nanostructures and reducing light reflection, leading to enhanced emission performance.
Implementation Method 1
a plurality of light-emitting nanostructures, each of which extends through each of the plurality of openings and includes a nanocore formed of a first conductivity-type semiconductor, an active layer and a second conductivity-type semiconductor shell layer
Implementation Method 2
The omnidirectional reflector may include first and second refraction layers having different refractive indices
Implementation Method 3
a reflective metal layer disposed on the contact electrode layer
Data Source
AI summary
A nanostructure semiconductor light-emitting device includes a base layer formed of a first conductivity-type semiconductor, a first material layer disposed on the base layer and including a plurality of openings, a plurality of light-emitting nanostructures, each of which extends through each of the plurality of openings and includes a nanocore formed of a first conductivity-type semiconductor, an active layer and a second conductivity-type semiconductor shell layer, sequentially disposed on the nanocore, a filling layer disposed on the first material layer, wherein the filling layer fills spaces between the plurality of light-emitting nanostructures and a portion of each of the plurality of light-emitting nanostructures is exposed by the filling layer, a second conductivity-type semiconductor extension layer disposed on the filling layer and covering the exposed portion of each of the plurality of light-emitting nanostructures, and a contact electrode layer disposed on the second conductivity-type semiconductor extension layer.