Semiconductor Laser Optical Guide Layer Doping Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
InAlGaP-based semiconductor laser elements face challenges with high electric and thermal resistance, leading to reduced lifetime and increased heat generation, due to p-type dopant diffusion and high carrier concentrations in optical guide layers, which conventional doping techniques have been unable to adequately address.
Innovation Solution
The semiconductor laser element incorporates an optical guide layer with a dopant to achieve a carrier concentration of 3.0×10^17 cm^-3 or higher, reducing element resistance and extending lifetime by controlling dopant distribution and interlattice atom formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high concentration doping is applied in p-type cladding layers to lower element resistance, then electric resistance decreases, but p-type dopant diffuses into the quantum-well active layer creating non-radiative recombination centers that reduce lifetime
Solution Approach 1:
The patent segments the cladding layer structure into multiple layers with different doping concentrations. The first p-type cladding layer has high doping concentration to reduce resistance, while the second p-type cladding layer has low doping concentration to prevent dopant diffusion into the active layer, thus resolving the contradiction between low resistance and long lifetime
Solution Approach 2:
The second p-type cladding layer with low doping concentration acts as an intermediary barrier between the high-doped first cladding layer and the quantum-well active layer, preventing direct dopant diffusion while maintaining the electrical benefits of high doping in the first layer
2Loss of energy
If p-type dopant diffuses into the optical guide layer increasing carrier concentration, then element resistance decreases, but defects become non-radiative recombination centers deteriorating characteristics
Solution Approach 1:
The patent applies local quality by creating a specific region (second p-type cladding layer) with low doping concentration adjacent to the optical guide layer and active layer, allowing controlled dopant distribution that reduces resistance without creating harmful defects in critical regions
3Illumination intensity
If InAlGaP-based material is used for optical guide layers, then light emission in 650 nm band is achieved, but electric resistance and thermal resistance increase requiring higher driving current and generating greater heat
Solution Approach 1:
The patent changes the doping concentration parameter in the cladding layers, using high doping concentration in the first p-type cladding layer to reduce electric resistance and compensate for the inherently higher resistance of InAlGaP-based materials, thereby enabling efficient operation without excessive heat generation
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 approach results in a semiconductor laser element with reduced electric and thermal resistance, enabling operation at lower voltages, reduced heat generation, and a significantly longer lifetime, even at low output power levels, while maintaining reliable performance in POF communication applications.
Implementation Method 1
the whole or a portion of the optical guide layer contains a dopant so as to realize a carrier concentration of 3.0×10^17 cm^-3 or higher
Data Source
AI summary
In a semiconductor laser element: a lower cladding layer of a first conductivity type, a quantum-well active layer, an upper cladding layer of a second conductivity type, a contact layer of the second conductivity type, and a first electrode of the second conductivity type are formed in this order above a surface of a semiconductor substrate of the first conductivity type, and a second electrode of the first conductivity type is formed below the lower cladding layer. An optical guide layer is arranged between the quantum-well active layer and one or each of the lower cladding layer and the upper cladding layer. The whole or a portion of the optical guide layer contains a dopant so as to realize a carrier concentration of 3.0×1017 cm−3 or higher.