DUV-LED Recessed Electrode Ohmic Contact Voltage Reduction
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Solution Overview
Problem
Deep ultra-violet light-emitting diodes (DUV-LEDs) face challenges with high operating voltage due to poor lateral current propagation and difficulty in forming ohmic contacts, which reduces their luminous efficacy and light extraction efficiency, especially for lateral light emission.
Innovation Solution
A light-emitting device design featuring a substrate with an epitaxial structure and electrodes, where the first electrode is partially covering the inner surface of the first type semiconductor layer, forming an ohmic contact and reducing the operating voltage, and the second electrode is on the second type semiconductor layer, enhancing light extraction by blocking waveguide effects and increasing the contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If DUV-LED uses high aluminum content epitaxial layer, then deep ultra-violet light emission is achieved, but ohmic contact formation becomes difficult and operating voltage increases
Solution Approach 1:
The patent applies local quality by creating a specific recess structure (first recess) at the contact region between the electrode and the first type semiconductor layer. This localized structural modification improves ohmic contact formation only at the necessary contact points without altering the overall high aluminum content composition required for DUV emission, thus reducing operating voltage while maintaining deep ultra-violet light emission capability
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 design reduces the operating voltage and enhances light extraction efficiency by improving current flow and light reflection, specifically for DUV-LEDs with lateral light emission.
Implementation Method 1
The first electrode is disposed in the second recess, at least partially covers the inner surface of the first type semiconductor layer, and is electrically connected to the first type semiconductor layer
Implementation Method 2
When a forward voltage is applied to the p-n junction structure, electrons move from the n-type region toward the p-type region while holes move toward the p-type region. The electrons and the holes are combined near the p-n junction, resulting in release of energy in the form of light that is emitted by the LED
Implementation Method 3
enhancing light extraction by blocking waveguide effects
Data Source
AI summary
A light-emitting device includes an epitaxial light-emitting structure formed on a substrate, a first electrode and a second electrode. The epitaxial light-emitting structure sequentially includes: a first type semiconductor layer including an Al component and electrically connected to the first electrode; an active layer; a second type semiconductor layer electrically connected to the second electrode; a first recess extending from the second type semiconductor layer to the first type semiconductor layer and having a projected area on the substrate ranging from 20% to 70% of that of the epitaxial light-emitting structure; and a second recess extending from the first type semiconductor layer toward the substrate. A light-emitting apparatus is also disclosed.