Transistor Laser Base Region Quantum Wells
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Solution Overview
Problem
Current transistor lasers and light-emitting transistors face limitations in efficiency and flexibility, particularly in high-speed operations and signal processing, due to challenges in controlling recombination and modulation processes.
Innovation Solution
A three-terminal semiconductor device with a collector tunnel junction and quantum size effects in the base region, allowing for efficient light emission and laser operation through electrical signal control, including reverse biasing and optical resonant cavities, which enhances carrier recombination and photon-assisted tunneling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional transistor structures are used for light emission, then device simplicity is maintained, but external quantum efficiency is limited
Solution Approach 1:
The device is segmented into distinct functional regions: a tunnel junction region for efficient carrier injection and a separate light emission region with quantum wells. This segmentation allows optimization of each region for its specific function, achieving high external quantum efficiency while maintaining manufacturing simplicity through standardized heterojunction bipolar transistor fabrication processes
Solution Approach 2:
The quantum well structures are nested within the base region of the heterojunction bipolar transistor. This nesting integrates the light emission function within the existing transistor architecture, improving external quantum efficiency without adding separate device structures, thereby maintaining ease of manufacture
2Ease of operation
If standard modulation methods are used, then operational simplicity is maintained, but modulation speed is limited
Solution Approach 1:
The patent replaces conventional current-based modulation mechanisms with voltage-based modulation through the tunnel junction. This substitution leverages the fast response characteristics of tunneling currents, achieving high modulation speeds while maintaining operational simplicity through voltage control rather than complex current modulation schemes
Solution Approach 2:
The invention changes the control parameter from current to voltage through the implementation of the tunnel junction. This parameter change enables faster modulation speeds by exploiting the voltage-dependent tunneling effect, while the device remains operationally simple through standard voltage biasing procedures
3Loss of energy
If quantum wells are added to enhance recombination control, then light emission efficiency is improved, but device complexity increases
Solution Approach 1:
The quantum wells are merged with the base region of the heterojunction bipolar transistor, combining the carrier confinement function of the transistor base with the radiative recombination function of the quantum wells. This merging achieves high recombination efficiency while avoiding the complexity of separate quantum well devices by integrating both functions into a single unified structure
4Adaptability or versatility
If feedback loops are implemented for signal processing, then signal processing capability is improved, but coupling losses increase
Solution Approach 1:
The tunnel junction provides self-service feedback by directly converting optical signals back into electrical signals through the photovoltaic effect within the same device structure. This self-service mechanism enables signal processing feedback loops without requiring external coupling components, thereby improving signal processing capability while minimizing coupling losses
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 enables direct voltage modulation, high external quantum efficiency, and improved signal processing capabilities, including efficient feedback loops and reduced coupling losses, enhancing the operational flexibility and efficiency of transistor lasers.
Implementation Method 1
a collector tunnel junction... reverse biasing the tunnel junction, whereby electrons injected into the base region, via the emitter, recombine, in the base region, with holes generated by the tunnel junction contributing to the laser emission
Implementation Method 2
providing, in the base region, a region exhibiting quantum size effects
Implementation Method 3
providing an optical resonant cavity enclosing at least a portion of the base region
Data Source
AI summary
A method for producing light emission from a semiconductor device includes the following steps: providing a semiconductor base region disposed between a semiconductor emitter region and a semiconductor collector region that forms a tunnel junction adjacent the base region; providing, in the base region, a region exhibiting quantum size effects; providing an emitter terminal, a base terminal, and a collector terminal respectively coupled with the emitter region, the base region, and the collector region; and applying electrical signals with respect to the emitter terminal, the base terminal and the collector terminal to produce light emission from the base region.