Light Emitting Device Reflector Busbar Current Blocking
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Solution Overview
Problem
Semiconductor light emitting devices face challenges in achieving uniform current distribution and efficient light extraction due to the short current spreading distance in thin layers, which can lead to absorption of light by metal busbars and reduced efficiency.
Innovation Solution
A current blocking structure is implemented by removing or not forming the light emitting layer in specific regions beneath the metal busbar, and a reflector is placed between the busbar and the semiconductor structure to prevent current injection and enhance light extraction, while the busbar itself is made partially reflective to minimize absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the light emitting layer is removed or not formed beneath the metal busbar to prevent current injection, then current distribution uniformity is improved, but light extraction efficiency deteriorates due to absorption by the metal busbar
Solution Approach 1:
A reflector layer is introduced as an intermediary component between the metal busbar and the light emitting layer. This reflector prevents direct current injection into the light emitting layer beneath the busbar while simultaneously reflecting emitted light back into the active region, thereby preventing energy loss through busbar absorption and improving both current uniformity and light extraction efficiency
2Stability of the object's composition
If a reflector is placed between the busbar and the semiconductor structure to prevent current injection, then current confinement is improved, but device complexity increases
Solution Approach 1:
The reflector layer is designed to perform multiple functions simultaneously: it acts as a current blocking barrier to prevent direct injection into the light emitting layer, serves as a light reflector to improve extraction efficiency, and provides a structural interface between the busbar and semiconductor. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
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 solution improves light extraction and reduces absorption by the busbars, leading to increased efficiency and uniform current distribution, thereby enhancing the overall performance of semiconductor light emitting devices.
Implementation Method 1
a reflector is placed between the busbar and the semiconductor structure to prevent current injection and enhance light extraction
Data Source
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AI summary
Embodiments of the invention include a semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region. A metal busbar is disposed on the semiconductor structure. A first portion of the metal busbar is in direct contact with the semiconductor structure. A reflector is disposed between a second portion of the metal busbar and the semiconductor structure. A current blocking structure prevents current from being injected in the light emitting layer in a region below the first portion.