Quantum-Well Light-Emitting Structure for Low-Current Efficiency
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Solution Overview
Problem
Conventional light-emitting structures are not suitable for micro light-emitting diodes operating at low current densities due to instability in photoelectric conversion efficiency and unsatisfactory lattice quality in multi quantum well structures.
Innovation Solution
A light-emitting structure with an active layer comprising multiple quantum-well sections, each with varying bandgap and thickness configurations, and grown at different rates to reduce lattice mismatch and enhance carrier transport and recombination efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional light-emitting structure is used, then it can operate at high current density, but photoelectric conversion efficiency becomes unstable and drops sharply at low current density
Solution Approach 1:
The active layer is divided into multiple quantum well sections (first, second, third sections) with different bandgap configurations. Each section is optimized for different current density ranges, allowing the device to maintain stable photoelectric conversion efficiency across a wide current density range from nanoampere-level to higher currents.
Solution Approach 2:
Different quantum well sections have locally optimized properties: the first section has specific bandgap for low current stability, the second section has intermediate properties, and the third section has properties optimized for higher current operation. This local differentiation enables the device to adapt to different operating conditions.
2Productivity
If multi quantum well structure is used, then light-emitting efficiency can be improved, but lattice quality becomes unsatisfactory due to lattice mismatch
Solution Approach 1:
The bandgap parameters of the quantum well sections are systematically varied: the first section has a first bandgap, the second section has a second bandgap, and the third section has a third bandgap. By carefully controlling these parameter changes, the patent achieves both high light-emitting efficiency and acceptable lattice quality across different operating conditions.
3Productivity
If quantum well structure with varying bandgap is used, then carrier transport and recombination efficiency can be enhanced, but device complexity increases
Solution Approach 1:
The active layer is segmented into three distinct quantum well sections, each with optimized bandgap for specific carrier transport and recombination functions. This segmentation enables enhanced overall efficiency while maintaining a structured and manageable device architecture.
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 proposed structure improves photoelectric conversion efficiency and reduces carrier overflow, enhancing light-emitting efficiency at low current densities and improving lattice quality.
Implementation Method 1
The active layer has N quantum-well structure periods. Each of the N quantum-well structure periods has a well layer and at least one barrier layer. The barrier layers of the N1 quantum-well structure periods of the first light-emitting section have an average bandgap less than that of the N2 quantum-well structure periods of the second light-emitting section.
Implementation Method 2
a light-emitting structure includes an n-type layer, an active layer, and a p-type layer... The p-type layer is disposed on the active layer and opposite to the n-type layer... enhancing light-emitting efficiency at low current densities
Data Source
AI summary
A light-emitting structure includes an n-type layer, an active layer, and a p-type layer. The active layer has N quantum well structure periods, each of the N quantum-well structure periods has a well layer and at least one barrier layer. The N quantum-well structure periods include a first light-emitting section and a second light-emitting section. The first light-emitting section is closer to the n-type layer than the second light-emitting section. A method for producing the light-emitting structure, and a light-emitting device that has the light-emitting structure are also disclosed.