InGaAsP Semiconductor Light-Emitting Element with Roughened Surface
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Solution Overview
Problem
Bonding-type semiconductor light-emitting elements exhibit multiple emission peaks in addition to the central peak, which can interfere with applications such as sensors and surveillance cameras, limiting their effectiveness.
Innovation Solution
A semiconductor light-emitting element with a cladding layer made of InGaAsP containing In and P, featuring a roughened surface on the light extraction side with a surface roughness of 0.03 μm or more and a random irregularity pattern, which reduces multipeaks to achieve a single peak in the emission spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a bonding-type semiconductor light-emitting element is used to improve light extraction efficiency, then external extraction efficiency is improved, but multiple emission peaks appear in the emission spectrum
Solution Approach 1:
The invention applies local quality by creating a roughened surface specifically on the light extraction side cladding layer, while keeping other parts of the device structure intact. This localized surface modification with Ra≥0.03μm selectively affects light extraction in the upward direction without altering the overall device architecture, thereby improving external extraction efficiency while maintaining spectral purity through suppressed vertical cavity modes.
Solution Approach 2:
The invention changes the surface roughness parameter of the light extraction side cladding layer to Ra≥0.03μm, which fundamentally alters the light extraction characteristics. This parameter change suppresses the formation of vertical cavity modes that cause multiple emission peaks, while simultaneously enhancing light extraction efficiency by scattering light at the roughened interface.
2Object-generated harmful factors
If the surface roughness is increased to reduce multipeaks, then emission spectrum purity is improved, but light extraction efficiency may be affected
Solution Approach 1:
The invention optimizes the surface roughness parameter to a specific threshold (Ra≥0.03μm) that simultaneously achieves two objectives: suppressing vertical cavity modes to eliminate multiple emission peaks, and enhancing light extraction efficiency through scattering effects. This precise parameter control resolves the contradiction by finding the optimal roughness value that benefits both spectral purity and light extraction.
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 solution effectively eliminates secondary emission peaks, enhancing the light emission output power and maintaining high efficiency even during continuous operation, thereby improving the performance of semiconductor light-emitting elements.
Implementation Method 1
a surface of a light extraction face of the second conductivity type cladding layer being a roughened surface which has a surface roughness Ra of 0.03 μm or more and has a random irregularity pattern
Data Source
AI summary
A semiconductor light-emitting element comprises, in this order, a substrate, a reflective layer, a first conductivity type cladding layer made of InGaAsP containing at least In and P, a semiconductor light-emitting layer having an emission central wavelength of 1000 nm to 2200 nm and a second conductivity type cladding layer made of InGaAsP containing at least In and P, the second conductivity type cladding layer being configured to be on a light extraction side, a surface of a light extraction face of the second conductivity type cladding layer being a roughened surface which has a surface roughness Ra of 0.03 μm or more and has a random irregularity pattern. The surface of the light extraction face has a skewness Rsk of −1 or more, and a protective film is provided on the light extraction face.