Micro-LED GaP Window Layer for Low-Current Luminous Efficiency
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Solution Overview
Problem
Micro light-emitting diodes (mLEDs) experience low luminous efficiency due to non-radiative recombination caused by sidewall defects, especially at low current densities, as their size decreases.
Innovation Solution
Incorporating an N-type gallium phosphide (GaP) window layer with a thickness of 100-2000 nanometers in the semiconductor epitaxial stacked layer to improve current spreading and reduce sidewall recombination, while also serving as an ohmic contact layer to enhance light transmittance and reduce absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the size of mLED is reduced to achieve ultra-high resolution, then the resolution is improved, but the sidewall defect density increases causing more severe non-radiative recombination
Solution Approach 1:
An N-type GaP window layer is introduced as an intermediary between the active layer and the contact layer. This window layer serves as a mediator that facilitates electron transport while reducing the impact of sidewall defects, thereby mitigating non-radiative recombination losses in miniaturized LEDs
Solution Approach 2:
The window layer changes the electrical and optical parameters of the device structure by providing a dedicated electron transport pathway with optimized doping concentration and thickness, which reduces carrier accumulation at defective sidewall regions and minimizes non-radiative recombination
2Use of energy by moving object
If the current density is reduced to operate at low power, then the power consumption is reduced, but the luminous efficiency decreases due to sidewall recombination
Solution Approach 1:
The N-type GaP window layer acts as an intermediary that enables efficient electron transport even at low current densities by providing a low-resistance pathway that bypasses the high-recombination sidewall regions, thereby maintaining high luminous efficiency at low power operation
Solution Approach 2:
The window layer creates a localized high-quality electron transport region with optimized doping and material properties, concentrating current flow through the center of the device away from defective sidewall areas, which maintains efficient recombination in the active layer even at low overall current densities
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 N-type GaP window layer increases electron mobility, reducing sidewall recombination and enhancing luminous efficiency by allowing more electrons to recombine in the active layer and improving light transmission through the metal electrode reflection, thereby increasing the micro light-emitting diode's efficiency at low current densities.
Implementation Method 1
the N-type GaP window layer is configured to play a role in current spreading... the N-type GaP has a high electron mobility
Implementation Method 2
the N-type GaP has better light transmittance than aluminum gallium indium phosphide (AlGaInP), which can increase the transmission of light emitted by the active layer, and then radiate from the light-emitting surface through the reflection of the metal electrode
Data Source
AI summary
A micro light-emitting diode and a display panel are provided. The micro light-emitting diode includes a semiconductor epitaxial stacked layer including a first semiconductor layer, a second semiconductor layer and an active layer therebetween; a first electrode electrically connected to the first semiconductor layer, and a second electrode electrically connected to the second semiconductor layer. The second semiconductor layer includes an N-type gallium phosphide (GaP) window layer, and the N-type GaP window layer plays a role in current spreading. The problem of low luminous efficiency of the micro light-emitting diode at a low current density can be solved and the luminous efficiency of the micro light-emitting diode at a low current density can be improved.