Photonic Crystal Surface Emitter for Current-Guided Light Output
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Solution Overview
Problem
Current surface-emitting semiconductor light-emitting devices have limitations in enhancing light output, particularly in controlling the propagation direction and intensity of emitted light.
Innovation Solution
Incorporating a photonic crystal layer with specific periodic structures and protrusions, along with a second semiconductor layer having varying impurity concentrations, to create high and peripheral current density regions that control current flow and enhance light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional semiconductor light-emitting device structure is used, then the device is simple to manufacture, but the light output intensity is limited
Solution Approach 1:
The device is segmented into distinct functional regions: a light-emitting region with high current density and an outer wall region with low current density. This segmentation allows optimized light output from the emitting region while the outer wall region provides structural stability and controlled current distribution, resolving the contradiction between intensity enhancement and structural simplicity.
Solution Approach 2:
Different regions of the device are assigned different electrical properties through selective doping. The light-emitting region has high carrier concentration for intense light generation, while the outer wall region has low carrier concentration to prevent current leakage and maintain structural integrity. This local quality differentiation enables high light output without requiring complex overall device redesign.
2Ease of operation
If uniform impurity concentration is used throughout the semiconductor layer, then the manufacturing process is simple, but current density control and emission directionality are poor
Solution Approach 1:
The semiconductor layer employs non-uniform impurity distribution with a first region (light-emitting) having higher carrier concentration than the second region (outer wall). This local quality variation enables precise current density control in the emitting region while maintaining manufacturing feasibility through selective doping processes during layer formation.
Solution Approach 2:
The semiconductor layer with gradient impurity distribution acts as an intermediary that mediates between the power supply and the active light-emitting region. It controls current flow distribution, directing high current density to the emitting region while limiting current in the outer wall region, thus achieving ease of operation without excessive manufacturing complexity.
3Illumination intensity
If high current density is applied throughout the entire device, then light emission intensity increases, but current leakage and energy loss increase
Solution Approach 1:
The device structure segments current flow paths into a high current density path through the light-emitting region and a low current density path through the outer wall region. This segmentation ensures intense light emission from the emitting region while minimizing current leakage and energy loss in the outer wall region, resolving the contradiction between emission intensity and energy efficiency.
Solution Approach 2:
Different regions exhibit different electrical characteristics: the light-emitting region has high carrier concentration to support high current density and intense light emission, while the outer wall region has low carrier concentration to suppress current leakage. This local quality differentiation achieves high light emission intensity without proportional energy loss.
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 configuration increases the intensity of laser light by controlling the current density and refractive index, resulting in improved light output and emission directionality.
Implementation Method 1
the photonic crystal layer includes a plurality of protrusions arranged along an upper surface of the active layer
Implementation Method 2
an active layer, provided on the first semiconductor layer
Data Source
AI summary
A surface-emitting semiconductor light-emitting device includes a first semiconductor layers, an active layer on the first semiconductor layer, a photonic crystal layer on the active layer and a second semiconductor layer on the photonic crystal layer. The photonic crystal layer include first protrusions in a first region and second protrusions in a second region. A spacing of adjacent first protrusions is greater than a spacing of adjacent second protrusions. The second semiconductor layer includes a first layer and a second layer on the first layer. The first layer covers first and second protrusions so that a first space remains between the adjacent first protrusions. The first layer includes a first portion provided between the adjacent second protrusions. The second layer includes a second portion provided between the adjacent first protrusions. The first space between the adjacent first protrusions is filled with the second portion of the second layer.