Quantum Well Light Emitter Structure for Better Carrier Injection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing nitride-based laser diodes for 3D printing are limited by poor crystalline quality of epitaxial layers due to the lack of a suitable substrate material, leading to low power output and inefficiencies in electron and hole carrier injection.
Innovation Solution
A light-emitting device with a substrate, a base layer of Al(x)Ga(1-x)N, and a diode layer structure comprising quantum wells and barrier layers, where the quantum wells are sandwiched between intrinsically doped GaN proximal barrier layers and Al(a)Ga(1-a)N distal barrier layers, separated from n- and p-doped semiconductor layers, enhancing crystalline quality and carrier injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional substrate materials are used for GaN-based laser diodes, then manufacturing is feasible, but crystalline quality of epitaxial layers deteriorates due to lattice mismatch and thermal expansion differences
Solution Approach 1:
The patent introduces an AlN base layer as an intermediary between the conventional substrate and the GaN-based quantum well layer structure. This base layer serves as a mediator that improves crystalline quality by providing a better lattice match for subsequent GaN layers, while still allowing the use of conventional substrates for manufacturing.
Solution Approach 2:
The patent changes the material composition parameter by using AlN (aluminum nitride) instead of conventional substrates like sapphire or silicon carbide. AlN has a lattice constant and thermal expansion coefficient that are much closer to GaN, thereby improving the crystalline quality of epitaxial layers grown on top.
2Productivity
If quantum wells are placed close to doped semiconductor layers for efficient carrier injection, then carrier injection efficiency improves, but non-radiative recombination increases due to dopant-related defects
Solution Approach 1:
The patent segments the device structure into distinct regions: a quantum well layer structure with high crystalline quality separated from doped semiconductor layers by undoped or low-doped barrier layers. This segmentation allows efficient carrier injection while minimizing non-radiative recombination by keeping dopants away from the quantum wells.
Solution Approach 2:
The patent introduces undoped or low-doped barrier layers as intermediary layers between the doped semiconductor layers and the quantum wells. These intermediary layers act as buffers that prevent dopant-related defects from reaching the quantum wells, thereby reducing non-radiative recombination while still allowing efficient carrier injection.
3Reliability
If high doping levels are used in semiconductor layers for improved conductivity, then electrical conductivity improves, but non-radiative recombination centers increase near quantum wells
Solution Approach 1:
The patent applies local quality by having different doping levels in different regions of the device. The semiconductor layers far from quantum wells have high doping levels for good conductivity, while the barrier layers adjacent to quantum wells are undoped or low-doped to minimize non-radiative recombination. This spatial variation in doping quality optimizes both conductivity and radiative efficiency.
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 device achieves high output power and efficient electron and hole recombination, enabling high-power light emission with improved crystalline quality and reduced non-radiative recombination centers.
Implementation Method 1
the n-doped semiconductor layer is configured to inject electrons into the quantum well layer structure
Implementation Method 2
the p-doped semiconductor layer is configured to inject holes into the quantum well layer structure
Implementation Method 3
Charge carriers, i.e. electrons and holes, may be confined in the first and second quantum well by the proximal barrier layers
Implementation Method 4
The device emits light when forward biased
Data Source
Figure 1
Figure 2~4
Figure 5~8
AI summary
A device (1) for emitting light, the device (1) comprising: a substrate (2); a base layer (4) arranged on the substrate (2); a diode layer structure (10) arranged on the base layer (4), the diode layer structure (10) comprising a quantum well layer structure (30) sandwiched between an n-doped semiconductor layer (12) and a p-doped semiconductor layer (14); the quantum well layer structure (30) comprising a first (41) and second (42) quantum well, a first (51) and a second (52) proximal barrier layer, and a first (61) and a second (62) distal barrier layer, wherein the first (41) and second (42) quantum wells and the first (51) and second (52) proximal barrier layers are sandwiched between the first (61) and second (62) distal barrier layers