Monolayer Nanocavity Laser With Monolithic LED Pump Integration
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Solution Overview
Problem
Current nanolasers face limitations in achieving enhanced light output and efficient integration into compact devices, such as integrated circuits, due to challenges in maximizing output power and minimizing footprint.
Innovation Solution
A monolithically integrated laser structure is developed, featuring a light emitting diode (LED) as an optical pump, a photonic crystal layer, and a monolayer semiconductor nanocavity laser, with a III-V buffer layer and a substrate of Si or Ge, to enhance light output and reduce dislocation defects, utilizing materials like WSe2 for efficient light pumping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional nanolaser structures are used, then device integration is achieved, but output power is insufficient
Solution Approach 1:
The patent merges the LED pump source and nanolaser into a monolithically integrated structure, where the LED is directly formed on the same substrate as the nanolaser cavity. This integration eliminates the need for separate pump sources and complex coupling mechanisms, thereby increasing output power while managing device complexity through unified fabrication.
Solution Approach 2:
The patent employs a vertical cavity structure where the LED and nanolaser are stacked in the vertical dimension rather than placed side-by-side. This vertical integration allows for compact footprint while maintaining high output power, resolving the contradiction between power output and device complexity by utilizing the third dimension.
2Area of stationary object
If nanolaser footprint is reduced for compact devices, then integration efficiency increases, but light output enhancement is limited
Solution Approach 1:
By transitioning to a vertical cavity architecture, the patent confines the laser action to the vertical dimension while minimizing horizontal footprint. The microdisk or micropillar cavity structure provides optical confinement in the radial direction, enabling compact lateral dimensions without sacrificing light output enhancement through vertical optical field concentration.
Solution Approach 2:
The patent employs composite material structures including III-V semiconductor layers for the active region, dielectric materials for the cavity, and metal contacts for electrical pumping. This composite approach enables compact integration while maintaining high light output through optimized material properties and interfaces.
3Reliability
If III-V buffer layer is used on Si substrate, then lattice mismatch is reduced, but dislocation defects occur
Solution Approach 1:
The patent segments the buffer layer into multiple III-V compound semiconductor layers with gradually changing composition (e.g., AlGaAs with varying Al content). This compositional grading progressively transitions the lattice constant from Si to the final active layer material, reducing misfit dislocations while maintaining crystal quality and 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 configuration significantly increases output power, enables efficient integration into compact devices, and supports on-chip lasing applications by maximizing efficiency and power while minimizing device size.
Implementation Method 1
a light emitting diode (LED) formed on a second surface of the buffer layer and configured to produce visible light
Implementation Method 2
a lens disposed on the LED to focus the visible light to output focused light
Implementation Method 3
a photonic crystal layer formed on the LED to receive the focused light
Implementation Method 4
a nanocavity laser formed on the photonic crystal layer and including a monolayer of a transition metal dichalcogenide having a chemical formula of MX2 for receiving the focused light through the photonic crystal layer to optically pump the nanocavity laser
Data Source
AI summary
A laser structure including a Si or Ge substrate, a III-V buffer layer formed on the substrate, a light emitting diode (LED) formed on the buffer layer configured to produce visible light, a lens disposed on the LED to focus light from the LED, a photonic crystal layer formed on the LED to receive the light focused by the lens, and a monolayer semiconductor nanocavity laser formed on the photonic crystal layer for receiving light through the photonic crystal layer from the LED. The LED and the laser are formed monolithically and the LED acts as an optical pump for the laser.