ZnO Quantum Well Light Emitter for Crack-Resistant Emission
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Solution Overview
Problem
Existing light emitting elements face challenges in maintaining emission efficiency due to fabrication defects such as cracks and pin-holes in semiconductor layers, which affect the overall performance and reliability of the devices.
Innovation Solution
A light emitting element is designed with an N-type semiconductor layer made of zinc oxide, a P-type semiconductor layer made of GaN, and an active layer featuring a quantum well structure with a barrier layer and a well layer, where the well layer is composed of zinc oxide, and the layers are formed using a method that includes forming mixed layers by mixing materials for the N-type and P-type semiconductor layers to prevent lattice mismatch and strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor layers are used in light emitting elements, then fabrication is relatively simple, but cracks and pin-holes form during the fabrication process reducing emission efficiency
Solution Approach 1:
The active layer is segmented into multiple quantum well structures with alternating barrier layers and well layers. This segmentation allows for better strain management and prevents crack formation while maintaining high emission efficiency. Each quantum well layer can be independently optimized for specific material composition and thickness.
Solution Approach 2:
The patent employs composite material structures where the N-type semiconductor layer uses zinc oxide semiconductor and the P-type semiconductor layer uses GaN. This composite approach leverages the complementary properties of different materials to achieve both high emission efficiency and fabrication reliability by matching lattice constants and reducing thermal stress.
2Reliability
If zinc oxide semiconductor is used in the N-type layer without doping, then material purity is maintained, but oxygen vacancies may affect semiconductor properties
Solution Approach 1:
The patent controls the oxygen vacancy concentration in zinc oxide semiconductor by adjusting fabrication parameters such as deposition temperature, oxygen partial pressure, and annealing conditions. This parameter optimization allows achieving the desired carrier concentration and semiconductor properties while maintaining material purity and minimizing harmful defects.
3Manufacturing precision
If mixed layers are formed by mixing N-type and P-type semiconductor materials, then lattice mismatch is reduced, but fabrication process complexity increases
Solution Approach 1:
The quantum well structure acts as an intermediary layer between the N-type zinc oxide semiconductor layer and the P-type GaN layer. This intermediate structure gradually transitions between the two different materials, reducing lattice mismatch and thermal stress while allowing each layer to be fabricated using optimized processes for its specific material system.
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 configuration enhances light emission efficiency by preventing fabrication defects and strain, thereby improving the reliability and performance of the light emitting element.
Implementation Method 1
Light may be emitted from the active layer by recombination of electrons and holes
Data Source
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AI summary
A light emitting element includes an N-type semiconductor layer including a zinc oxide semiconductor, a P-type semiconductor layer, and an active layer disposed between the N-type semiconductor layer and the P-type semiconductor layer. The active layer has a quantum well including a barrier layer and a well layer including zinc oxide.