Auger Carrier Injection III-Nitride LED for Safe UV Disinfection
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Solution Overview
Problem
Current methods for generating UV-C light are either toxic, harmful to the environment, or ineffective in disinfecting surfaces and water due to the lack of a stable, non-toxic, and efficient solid-state UV-C light source.
Innovation Solution
A III-nitride-based LED device that emits both visible and UV light using Auger carrier injection, specifically utilizing a wide band-gap impurity-doped AlGaN layer to produce far UV-C light, which is safe for human exposure and effective in disinfection applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional UV-C light sources are used for disinfection, then effective germicidal action is achieved, but toxicity and environmental harm occur
Solution Approach 1:
The invention changes the wavelength parameter of UV light from conventional UV-C (200-280 nm) to far UV-C (200-230 nm), specifically targeting 222 nm emission. This parameter change maintains germicidal effectiveness while reducing harmful effects on human tissue, as the shorter wavelength is absorbed by the outer dead layer of skin rather than penetrating to living cells.
Solution Approach 2:
The patent employs a solid-state LED structure that replaces traditional mercury vapor lamps and other toxic UV sources. The LED uses a simple p-n junction diode design with no hazardous materials, making it a safe, environmentally friendly alternative that eliminates the need for disposal of toxic components.
2Object-affected harmful factors
If solid-state UV-C LED is developed for safe disinfection, then human safety is improved, but device complexity increases due to novel carrier injection mechanism
Solution Approach 1:
The invention converts the typically harmful Auger recombination process, which causes efficiency droop in conventional LEDs, into a beneficial carrier injection mechanism. By designing the device to utilize Auger-generated hot carriers as the primary injection method into the p-type layer, the patent transforms a loss mechanism into the core operating principle that enables far UV-C emission while maintaining simple device structure.
Solution Approach 2:
The device structure enables self-injection of carriers through Auger recombination in the InGaN active region, which automatically generates hot carriers that are injected into the AlGaN p-type layer. This self-service mechanism eliminates the need for complex external carrier injection structures, simplifying the overall device design while achieving the desired far UV-C emission.
3Illumination intensity
If Auger carrier injection is used for UV emission, then far UV-C light is generated, but efficiency droop occurs at high current densities
Solution Approach 1:
The patent fundamentally reinterprets Auger recombination from a harmful efficiency-loss mechanism to the primary useful function. By designing the device so that Auger-generated hot carriers directly inject into the p-type AlGaN layer to produce far UV-C emission, the typically wasted energy is converted into the desired output, eliminating efficiency droop rather than causing it.
Solution Approach 2:
The invention changes the dominant recombination mechanism parameter from radiative recombination (in conventional LEDs) to Auger recombination followed by hot carrier injection. This parameter change in the physical process enables far UV-C emission while utilizing the Auger process that would normally cause efficiency droop, thereby converting the droop mechanism into the driving force for useful emission.
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 device efficiently generates far UV-C light with a wavelength of 200-230 nm, effectively disinfecting surfaces and water while being harmless to humans, offering a safe and sustainable solution for disinfection in various settings.
Implementation Method 1
The visible light is emitted from an InGaN active region
Implementation Method 2
a novel Auger carrier injection method is proposed for injection of electrons into a wide band-gap impurity-doped AlGaN layer, for example, a p-type AlGaN layer, for emission of the UV light
Implementation Method 3
for injection of electrons into a wide band-gap impurity-doped AlGaN layer, for example, a p-type AlGaN layer, for emission of the UV light
Data Source
AI summary
A III-nitride LED with simultaneous visible and ultraviolet (UV) emission, in which the visible emission is due to conventional InGaN active region mechanisms and the UV emission occurs due to Auger carrier injection into a UV light emitting region, such as impurity-doped AlGaN. The primary application for the III-nitride LED is general airborne pathogen inactivation to prevent the transmission of airborne-mediated pathogens while being safe for humans.