Semiconductor Laser Asymmetric Carrier Blocking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor laser devices face challenges in achieving high-output operation while maintaining low current and low power consumption due to increased light density and thermal excitation, which leads to catastrophic optical damage and reduced luminous efficiency, primarily caused by high impurity concentrations in carrier blocking layers that increase internal loss and operating voltage.
Innovation Solution
The semiconductor laser device configuration includes a first semiconductor layer with a higher band gap energy, an active layer, and a third semiconductor layer with a lower band gap energy, where the impurity concentration of the second semiconductor layer is greater than the third, allowing efficient carrier confinement and reducing the potential barrier at the hetero interface, thereby decreasing free carrier loss and internal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high impurity concentration is used in carrier blocking layers to increase band gap energy, then carrier confinement is improved, but internal loss and operating voltage increase
Solution Approach 1:
The patent applies local quality by creating asymmetric impurity concentration distribution in the carrier blocking layers. The n-type carrier blocking layer has higher impurity concentration (1×10^18 to 1×10^19 cm^-3) compared to the p-type carrier blocking layer (1×10^17 to 1×10^18 cm^-3). This localized differentiation optimizes electron confinement in the n-type layer while minimizing hole concentration in the p-type layer, thereby reducing free carrier loss and internal absorption without compromising carrier confinement effectiveness.
Solution Approach 2:
The patent changes the impurity concentration parameter differently for n-type and p-type carrier blocking layers. By setting N2 (n-type impurity concentration) > N3 (p-type impurity concentration), the patent optimizes the balance between carrier confinement and loss reduction. This parameter differentiation allows the n-type layer to effectively block electrons while the p-type layer maintains adequate hole blocking with lower loss, resolving the contradiction between confinement and energy loss.
2Reliability
If high impurity concentration is used in carrier blocking layers, then carrier confinement is improved, but operating voltage increases
Solution Approach 1:
The patent applies local quality by creating asymmetric impurity concentration distribution in the carrier blocking layers. The n-type carrier blocking layer has higher impurity concentration (1×10^18 to 1×10^19 cm^-3) compared to the p-type carrier blocking layer (1×10^17 to 1×10^18 cm^-3). This localized differentiation optimizes electron confinement in the n-type layer while minimizing hole concentration in the p-type layer, thereby reducing free carrier loss and internal absorption without compromising carrier confinement effectiveness.
Solution Approach 2:
The patent changes the impurity concentration parameter differently for n-type and p-type carrier blocking layers. By setting N2 (n-type impurity concentration) > N3 (p-type impurity concentration), the patent optimizes the balance between carrier confinement and loss reduction. This parameter differentiation allows the n-type layer to effectively block electrons while the p-type layer maintains adequate hole blocking with lower loss, resolving the contradiction between confinement and energy loss.
3Productivity
If light density on end face is increased to achieve high output, then light output is improved, but catastrophic optical damage occurs
Solution Approach 1:
The patent converts the potentially harmful high light density at the end face into a beneficial effect by using it to excite carriers in the active layer, which then recombine to produce laser light. The asymmetric carrier blocking structure ensures that carriers are efficiently injected and confined in the active layer, maximizing light output while the optimized impurity concentrations prevent excessive heat generation and carrier leakage, thereby preventing catastrophic optical damage.
Solution Approach 2:
The patent optimizes multiple parameters including impurity concentrations (N2 > N3), band gap energies (Eg2 > Eg3), and layer thicknesses to achieve the desired balance. By carefully controlling these parameters, the patent enables high light output while maintaining reliability and preventing optical damage.
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 enhances the slope efficiency and heat saturation level, enabling high-output and low-current operation with reduced power consumption and improved reliability by minimizing carrier leakage and optical damage.
Implementation Method 1
a second semiconductor layer on the first conductivity side, the second semiconductor layer having band gap energy higher than band gap energy of the first semiconductor layer
Implementation Method 2
the impurity concentration of the second semiconductor layer is greater than the third, allowing efficient carrier confinement and reducing the potential barrier at the hetero interface, thereby decreasing free carrier loss and internal loss
Implementation Method 3
an active layer; a third semiconductor layer on a second conductivity side different from the first conductivity side
Data Source
AI summary
A semiconductor laser device includes: a first semiconductor layer on a first conductivity side; a second semiconductor layer on the first conductivity side; an active layer; a third semiconductor layer on a second conductivity side different from the first conductivity side; and a fourth semiconductor layer on the second conductivity side. Eg2<Eg3 is satisfied, where Eg2 and Eg3 denote maximum values of band gap energy of the second semiconductor layer and the third semiconductor layer, respectively. The third semiconductor layer includes a first region layer in which band gap energy monotonically decreases toward the fourth semiconductor layer. N2>N3 is satisfied, where N2 denotes an impurity concentration of the second semiconductor layer, and N3 denotes an impurity concentration of the third semiconductor layer.