Light-Emitting Organic Field-Effect Transistor With Integrated Waveguide
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Solution Overview
Problem
Current organic semiconductor lasers face challenges in achieving efficient electrically pumped lasing due to optical losses from electrodes and charge-carrier induced absorptions, with no suitable device architecture proven for electrically pumped organic semiconductor lasers.
Innovation Solution
A light-emitting organic field-effect transistor (LFET) integrated with a high refractive index ridge or rib waveguide and a distributed feedback (DFB) structure, where the recombination zone is positioned on top of the waveguide to efficiently couple light into the waveguide, reducing optical losses and allowing for electrical pumping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electrical pumping is used in organic semiconductor lasers, then light generation can be achieved through electrical stimulation, but optical losses occur due to electrode absorption and charge-carrier induced absorptions
Solution Approach 1:
The device is segmented into distinct functional regions: the gain medium layer for light generation, the waveguide layer for light confinement, and the cladding layers for optical isolation. This segmentation allows the gain medium to be positioned away from lossy electrodes while maintaining efficient electrical pumping through the ambipolar LFET channel.
Solution Approach 2:
The waveguide layer acts as an intermediary between the gain medium and the cladding layers, providing a low-loss optical pathway. The waveguide confines the optical mode within the gain medium region, preventing light from interacting with lossy electrodes and charge carriers, thereby reducing optical losses while maintaining electrical pumping efficiency.
2Reliability
If a high refractive index waveguide is integrated within the LFET channel, then optical feedback is improved and lasing threshold is lowered, but device structure becomes more complex
Solution Approach 1:
The waveguide structure is merged with the LFET device architecture, where the waveguide layer is integrated within the channel region. This combining approach provides efficient optical feedback for lasing while maintaining a relatively simple planar device structure that can be fabricated using standard thin-film deposition techniques.
Solution Approach 2:
The LFET channel serves multiple functions: it provides the gain medium for light generation through ambipolar injection, acts as the optical waveguide for light confinement and feedback, and functions as the active region for electrical pumping. This multi-functionality reduces the need for separate components and simplifies the overall device structure.
3Productivity
If the recombination zone is positioned on top of the waveguide, then light coupling into the waveguide is enhanced, but optical losses from electrodes increase
Solution Approach 1:
The optical mode confinement is optimized locally within the waveguide layer, creating a region of high optical intensity where the gain medium is positioned. This local quality enhancement ensures efficient light coupling into the waveguide while the cladding layers provide optical isolation from lossy electrodes, balancing coupling efficiency with loss reduction.
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 proposed architecture lowers lasing thresholds by providing efficient optical feedback and reducing optical losses, enabling the use of thinner gate dielectrics and achieving high LFET current and low optical losses, thus facilitating electrically pumped organic semiconductor lasers.
Implementation Method 1
a light-emitting organic field-effect transistor (LFET) integrated with a high refractive index ridge or rib waveguide
Implementation Method 2
a distributed feedback (DFB) structure, where the recombination zone is positioned on top of the waveguide to efficiently couple light into the waveguide
Implementation Method 3
light-emitting field-effect transistors... light generated by LEDs... light-emitting organic field-effect transistor (LFET)
Data Source
AI summary
The present invention relates integrated optoelectronic devices comprising light emitting field-effect transistors. We describe an optoelectronic device comprising a light-emitting field effect transistor (LFET) with an organic semiconductor active layer and a waveguide integrated within the channel of the light-emitting field effect transistor, wherein said waveguide comprises a material which has a higher refractive index than said organic semiconductor. We also describe a light-emitting organic field transistor integrated with a ridge or rib waveguide incorporated within the channel of the LFET; and a similar light-emitting organic field effect transistor in which the waveguide incorporates an optical feedback mechanism.