Graded Contact Structure for Light Emitting Device Voltage Reduction
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Solution Overview
Problem
Existing light-emitting devices face issues with high operation voltage, leading to high power consumption and low light efficiency, which needs to be reduced.
Innovation Solution
A light-emitting device structure comprising a substrate, a first light-emitting stack with a contact structure formed by first, second, and third contact layers, each containing a doping material, where the contact structure has a graded bandgap and specific doping concentrations to achieve p-type conductivity, allowing for efficient voltage reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional contact structures are used in light-emitting devices, then the device structure is simple, but the operation voltage is high leading to high power consumption and low light efficiency
Solution Approach 1:
The contact structure is divided into three distinct contact layers (first, second, and third contact layers) with different doping concentrations and bandgap energies. This segmentation allows each layer to be optimized for specific functions, reducing overall power consumption while managing the complexity through modular design
Solution Approach 2:
The patent changes key parameters of the contact layers including doping concentrations (ranging from 1×10^18 to 1×10^20 atoms/cm³) and bandgap energies (from 1.8 eV to 2.4 eV) to optimize electrical properties and reduce operation voltage, thereby lowering power consumption
2Use of energy by moving object
If conventional contact structures are used in light-emitting devices, then the device structure is simple, but the light efficiency is low
Solution Approach 1:
Each contact layer is assigned different local qualities through varying doping concentrations and bandgap energies. The first contact layer has higher doping concentration and lower bandgap, while the third contact layer has lower doping concentration and higher bandgap, creating optimized local electrical properties that improve overall light efficiency
Solution Approach 2:
The contact structure uses composite material design with three different contact layers, each having distinct material properties (doping concentrations and bandgap energies). This composite structure enables better charge carrier transport and reduces energy loss, thereby improving light efficiency while accepting increased structural complexity
3Reliability
If higher doping concentrations are used in contact layers, then the electrical conductivity is improved, but the bandgap energy decreases affecting light emission properties
Solution Approach 1:
The contact structure is segmented into three layers with progressively varying doping concentrations and bandgap energies. This segmentation allows the system to achieve high electrical conductivity through cumulative doping effects while maintaining stable light emission properties by ensuring each layer's bandgap remains within acceptable ranges
Solution Approach 2:
The patent systematically changes doping concentrations across the three contact layers (from 1×10^18 to 1×10^20 atoms/cm³) while controlling bandgap energies (from 1.8 eV to 2.4 eV) to achieve the optimal balance between electrical conductivity and light emission stability
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 effectively reduces the operation voltage and power consumption, enhancing light efficiency by optimizing the contact layers' doping concentrations and bandgaps, as demonstrated in experimental examples.
Implementation Method 1
Each of the first, second and third contact layers comprises a doping material
Data Source
AI summary
This disclosure discloses a light-emitting device. The light-emitting device comprises: a substrate; a first light-emitting stack comprising a first active layer; a bonding interface formed between the substrate and the first light-emitting stack; and a contact structure formed on the first light-emitting stack and comprising first, second and third contact layers. Each of the first, second and third contact layers comprises a doping material.