Dual Hexagonal Pyramid Hole Injection Layer for GaN LED Efficiency
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Solution Overview
Problem
The low hole concentration and mobility in P—GaN material limit the injection depth and light-emitting efficiency of GaN-based LEDs, and the quantum well grown on V pits forms a barrier that further reduces injection efficiency.
Innovation Solution
A dual hexagonal pyramid-shaped hole injection layer is formed in the multi-quantum well layer with V pits, reducing point defect and dislocation density, and embedding in the second conductive type semiconductor layer to enhance hole injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional planar hole injection layer is used, then the structure is simple, but the hole injection area is limited and injection efficiency is low
Solution Approach 1:
The hole injection layer is transformed from a conventional planar (2D) structure to a three-dimensional dual hexagonal pyramid structure. This dimensional change dramatically increases the hole injection area and provides more injection channels, thereby improving hole injection efficiency while maintaining structural clarity through the symmetric pyramid geometry.
2Productivity
If V pits are introduced to improve hole injection, then hole injection channels increase, but quantum well on side wall forms barrier reducing injection efficiency
Solution Approach 1:
The side wall quantum well that originally formed a barrier to hole injection is converted into a beneficial component. By designing the dual hexagonal pyramid structure, the side wall quantum well becomes an additional hole injection channel rather than a barrier, transforming the harmful effect into a beneficial contribution to overall hole injection efficiency.
Solution Approach 2:
The hole injection layer exhibits different properties in different regions: the central region provides primary hole injection, while the side wall regions with quantum wells provide additional injection channels. This local differentiation optimizes hole injection throughout the entire structure, utilizing both central and peripheral regions effectively.
3Stability of the object's composition
If P—GaN material is used for hole injection layer, then material compatibility is good, but low hole concentration and mobility limit injection depth
Solution Approach 1:
The hole injection layer is constructed as a composite structure combining P—GaN material with a dual hexagonal pyramid geometric configuration. This composite approach maintains the material compatibility and crystal structure benefits of P—GaN while the three-dimensional geometry compensates for low hole concentration and mobility by providing extended injection pathways and increased active injection area.
Data Source
AI summary
A light-emitting diode (LED) epitaxial structure includes, from bottom to up, a substrate, a first conductive type semiconductor layer, a super lattice, a multi-quantum well layer with V pits, a hole injection layer and a second conductive type semiconductor layer. The hole injection layer appears in the shape of dual hexagonal pyramid, which fills up the V pits and embeds in the second conductive type semiconductor layer. Various embodiments of the present disclosures can effectively reduce point defect density and dislocation density of semiconductor material and effectively enlarge hole injection area and improves hole injection efficiency.