LED Structure with Electron Blocking Layer for Current Crowding
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Solution Overview
Problem
Current light emitting diodes (LEDs) face issues with current crowding and efficiency droop, leading to reduced light output power and emission efficiency due to poor current spreading and electron confinement.
Innovation Solution
The implementation of a light emitting device structure featuring a first conductivity type semiconductor layer, an InxGa1-xN layer, a GaN layer, a first Al y1 Ga 1-y1 N layer, a GaN-based superlattice layer with reduced bandgap energy, and an active layer, which efficiently spreads current and confines electrons to enhance luminous intensity and light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If current is increased to improve luminous intensity, then light output power increases, but current crowding phenomenon occurs which lowers light output power
Solution Approach 1:
An electron blocking layer is introduced as an intermediary between the active layer and the P-type semiconductor layer. This layer selectively blocks electrons while allowing holes to pass through, preventing electron overflow into the P-type layer and thereby eliminating the current crowding phenomenon that occurs when high current is applied to improve luminous intensity
2Reliability
If electrons are allowed to flow freely to increase current, then electrical conductivity improves, but electrons overflow into P type semiconductor layer which lowers light emission efficiency
Solution Approach 1:
The electron blocking layer serves as a selective barrier that intercepts electrons before they can overflow into the P-type semiconductor layer. It allows holes to pass through to the active layer while blocking electrons, thus preventing energy loss from electron overflow and maintaining high light emission efficiency
3Power
If conventional LED structure is used, then manufacturing is simple, but current spreading is poor leading to reduced luminous intensity
Solution Approach 1:
The electron blocking layer is positioned between the active layer and P-type semiconductor layer to improve current spreading. By blocking electrons from entering the P-type layer, it forces current to spread more uniformly across the active layer, thereby increasing luminous intensity without requiring complex external current distribution structures
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 structure effectively addresses current crowding and efficiency droop by improving current spreading and electron confinement, resulting in increased luminous intensity and light emission efficiency, suitable for high-power LED applications.
Implementation Method 1
an In x Ga 1-x N layer, a GaN layer, a first Al y1 Ga 1-y1 N layer which forms a current spreading structure with the In x Ga 1-x N layer and the GaN layer
Implementation Method 2
a GaN-based superlattice layer having a bandgap energy level reduced in the direction from the first conductivity type semiconductor layer toward the active layer
Implementation Method 3
A light emitting device includes a P-N junction diode having a characteristic of converting electrical energy into light energy
Data Source
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AI summary
Disclosed are a light emitting device, a method of fabricating a light emitting device, a light emitting device package, and a lighting system. The light emitting device includes a first conductive semiconductor layer (112), an InxGa1-xN layer (where, 0<x≤1) (151) on the first conductive semiconductor layer (112), a GaN layer (152) on the InxGa1-xN layer (151), a first Aly1Ga1-y1N layer (where, 0<y1 ≤1) (153) on the GaN layer (152), an active layer (114) on the first Aly1Ga1-y1N layer (153), and a second conductive semiconductor layer (116) on the active layer (114).