2D Material Laser on Silicon via Buffer Layer
Solution Overview
Problem
The high cost and limited availability of III-V material substrates, such as GaAs, and the lattice and thermal expansion mismatches between Si and laser materials, lead to defects and hinder the widespread adoption of high-performance lasers on silicon substrates.
Innovation Solution
A laser structure is developed using a silicon substrate with a buffer layer and a multi-quantum well arrangement of alternating sub-wavelength dielectric and two-dimensional material layers, integrated with a light emitting diode (LED) for optical pumping, which reduces lattice mismatch and defect density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If III-V materials (e.g., GaAs) are used for high performance lasers, then laser performance is improved, but substrate cost increases and availability decreases
Solution Approach 1:
A buffer layer is introduced as an intermediary between the silicon substrate and the III-V laser materials. This buffer layer mediates the interface between dissimilar materials, reducing defect growth and enabling the combination of low-cost silicon substrates with high-performance III-V laser materials.
Solution Approach 2:
The patent employs a composite structure combining silicon substrate with III-V laser materials through a buffer layer. This composite approach allows leveraging the cost advantages of silicon while maintaining the high performance of III-V materials in the laser active region.
2Ease of manufacture
If silicon substrates are used to reduce cost, then substrate cost decreases, but lattice mismatch and thermal expansion differences cause defect growth
Solution Approach 1:
The buffer layer serves as a mediator between silicon and III-V materials, accommodating lattice mismatch and thermal expansion differences. This intermediary layer prevents defect propagation from the silicon substrate into the laser structure.
3Adaptability or versatility
If conventional laser structures are used on silicon, then integration is achieved, but defect reactions during lasing occur due to material mismatches
Solution Approach 1:
The buffer layer acts as a protective intermediary that prevents defect reactions during lasing operations. It isolates the III-V laser materials from the silicon substrate, allowing integration while maintaining laser reliability.
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 enables the creation of efficient, compact, and powerful nanolasers that can be integrated into IC devices, offering high output and low lasing threshold while avoiding the drawbacks of conventional nanolasers, such as small gain volumes and low output levels.
Implementation Method 1
a light emitting diode (LED) formed on the buffer layer
Implementation Method 2
optically pumped by a light emitting diode
Implementation Method 3
multi-quantum well is formed on the first dielectric layer and has a plurality of alternating layers... to form a multi-quantum well laser
Data Source
AI summary
A laser structure includes a substrate and a first dielectric layer formed on the substrate. A multi-quantum well is formed on the first dielectric layer and has a plurality of alternating layers. The alternating layers include a dielectric layer having a sub-wavelength thickness and a monolayer of a two dimensional material.