Electron Beam Pumping for UV Light Emission
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Solution Overview
Problem
Developing solid-state emitters that emit radiation in the ultraviolet range is challenging due to inefficiencies in p-type doping and carrier injection, material quality issues, and limitations in wavelength specificity, size, and operation mode of existing UV lasers, as well as difficulties in epitaxial growth of high-quality aluminum gallium nitride on mismatched substrates.
Innovation Solution
A light emitting semiconductor structure is excited by an electron beam impacting its lateral surface at a non-zero angle, utilizing wave guiding layers and other features to enhance light generation and operation, allowing for improved efficiency and flexibility in wavelength and mode of operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If frequency-doubled or -quadrupled lasers are used to achieve shortened wavelength output, then UV radiation can be generated, but precise alignment of optical components is required and the system becomes complex
Solution Approach 1:
The patent extracts the optical frequency conversion components (doublers, quadruplers) and replaces them with a direct electron beam pumping system that generates UV radiation without intermediate optical stages. This eliminates the complex alignment requirements while maintaining UV output capability
Solution Approach 2:
The patent replaces the mechanical/optical system (laser cavities, mirrors, frequency converters) with an electron beam system that directly pumps the semiconductor structure to generate UV light, substituting complex optical mechanics with a more straightforward electron-to-photon conversion process
2Manufacturing precision
If conventional UV lasers are used, then specific wavelengths can be achieved, but the devices are limited to very specific wavelengths and operate only in pulsed mode
Solution Approach 1:
The patent employs dynamic control of the electron beam parameters (energy, current, pulse duration) to enable continuous tuning of the emitted wavelength. The semiconductor structure can be dynamically adjusted by varying electron beam conditions, allowing operation across a range of wavelengths rather than fixed values
Solution Approach 2:
The patent changes the operating parameters of the electron beam (acceleration voltage, beam current, pulse width) to control the excitation level and resulting emission wavelength. By adjusting these parameters, the system can operate at different wavelengths and in different modes (continuous or pulsed)
3Illumination intensity
If excimer lasers are used for UV emission, then specific wavelengths can be achieved, but the devices are very bulky and immobile
Solution Approach 1:
The patent extracts the UV emission function from the bulky excimer laser system and implements it in a compact semiconductor structure pumped by an electron beam. This maintains UV emission capability while eliminating the large gas-filled chambers and high-voltage components of excimer lasers
Solution Approach 2:
The patent uses thin-film semiconductor structures and integrated electron beam sources that can be fabricated on small substrates, creating a compact, potentially flexible device that replaces the rigid, bulky excimer laser architecture
4Ease of manufacture
If epitaxial growth is performed on mismatched substrates, then device fabrication can proceed, but threading dislocations result in leakage currents and trapping effects
Solution Approach 1:
The patent applies local quality improvements by using electron beam pumping in specific regions of the semiconductor structure, allowing high-quality active regions to be maintained while managing dislocation effects in other areas. The electron beam can be focused to pump only the highest quality regions
Solution Approach 2:
The patent changes the operational parameters to compensate for material quality issues by using electron beam energy and flux control to optimize carrier generation and recombination processes, thereby maintaining device performance despite the presence of threading dislocations
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 more efficient and flexible light emission in the UV range, overcoming limitations in existing UV laser technologies by optimizing electron beam interaction with the semiconductor structure, improving carrier injection, and reducing material quality issues.
Implementation Method 1
a light emitting semiconductor structure is excited by an electron beam that impacts a region of a lateral surface of the light emitting semiconductor structure
Implementation Method 2
light emitting semiconductor structure having a lateral surface; and means for directing an electron beam over at least a portion of the lateral surface
Data Source
AI summary
A device is provided in which a light emitting semiconductor structure is excited by an electron beam that impacts a region of a lateral surface of the light emitting semiconductor structure at an angle to the normal of the lateral surface that is non-zero. The non-zero angle can be configured to cause excitation in a desired region of the light emitting semiconductor structure. The device can include wave guiding layer(s) and/or other features to improve the light generation and/or operation of the device.