Compositional Inhomogeneities in Semiconductor Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current deep ultraviolet light emitting devices have low wall plug operating efficiencies, and existing semiconductor materials like InGaN and AlGaN suffer from high dislocation densities and nonradiative recombination issues, limiting their emission efficiency.
Innovation Solution
Incorporating compositional inhomogeneous regions in semiconductor layers with a band gap difference of at least thermal energy and a characteristic size smaller than the inverse of dislocation density, enhancing radiative recombination and reducing nonradiative recombination times by isolating carriers from threading dislocation cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional semiconductor materials like InGaN and AlGaN are used, then device structure can be maintained, but high dislocation densities cause nonradiative recombination and low emission efficiency
Solution Approach 1:
The patent introduces compositional inhomogeneous regions with varying band gaps throughout the semiconductor layer. These localized regions with different material properties (lower band gap) create potential minima that trap carriers, transforming the uniform material structure into a heterogeneous one with spatially varying optical and electrical characteristics. This local quality variation enables carrier localization away from dislocation cores, improving radiative recombination efficiency despite high dislocation densities.
2Productivity
If compositional inhomogeneous regions are introduced to improve radiative recombination, then emission efficiency increases, but material composition uniformity decreases
Solution Approach 1:
The patent deliberately varies the compositional parameter (indium or aluminum concentration) to create regions with different band gap energies. By changing the composition parameter locally while maintaining overall structural integrity, the invention transforms a uniform compositional state into a controlled non-uniform state that enhances radiative recombination through carrier localization in potential minima.
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 approach improves internal quantum efficiency and reliability of the devices by preventing electrons from reaching dislocation cores, leading to enhanced light emission efficiency and longer radiative lifetimes.
Implementation Method 1
These compositional fluctuations, also known as localized inhomogeneities, result in carrier localization and lead to an enhancement in the radiative efficiency
Implementation Method 2
the luminescence occurs due to radiative recombination of carriers in the self-assembled nanometer-scale localized compositionally inhomogeneous regions
Implementation Method 3
a difference between an average band gap for the plurality of compositional inhomogeneous regions and an average band gap for a remaining portion of the semiconductor layer is at least thermal energy
Data Source
AI summary
A device comprising a semiconductor layer including a plurality of compositional inhomogeneous regions is provided. The difference between an average band gap for the plurality of compositional inhomogeneous regions and an average band gap for a remaining portion of the semiconductor layer can be at least thermal energy. Additionally, a characteristic size of the plurality of compositional inhomogeneous regions can be smaller than an inverse of a dislocation density for the semiconductor layer.