Ultraviolet Light Emitting Device Using Electron Beam Injection
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Solution Overview
Problem
Ultraviolet light emitting diodes face low efficiency due to challenges in forming p-type semiconductor layers, particularly for generating ultraviolet light, where dopant activation is difficult and conductivity is low, leading to limited market application despite increasing demand.
Innovation Solution
An ultraviolet light emitting device that uses an electron beam generator with carbon nanotubes to produce electron beams, which collide with a quantum well structure in the absence of a p-type semiconductor layer, generating electron-hole pairs and producing ultraviolet light through recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a p-type semiconductor layer is formed using conventional methods (MOCVD) with dopants, then the device structure is complete, but the efficiency is lowered due to insufficient hole concentration and low conductivity
Solution Approach 1:
The patent removes the p-type semiconductor layer entirely from the device structure. Instead of attempting to form a functional p-type layer through conventional doping methods, the invention extracts this problematic component and replaces it with an n-type semiconductor layer that receives electrons from an electron beam, thereby eliminating the efficiency losses associated with poor hole concentration and conductivity in p-type layers
Solution Approach 2:
The patent substitutes the conventional electrical doping mechanism (chemical vapor deposition with dopants) with a direct electron beam injection mechanism. Instead of relying on thermal diffusion of dopant atoms during MOCVD, the invention uses a focused electron beam to directly supply high-energy electrons to the active layer, achieving superior carrier injection efficiency
2Illumination intensity
If the wavelength of generated light is decreased toward ultraviolet range, then the bandgap energy of well layers is increased, but the efficiency is further lowered due to increased difficulty in forming functional p-type semiconductor layers
Solution Approach 1:
The patent changes the fundamental operating parameters of the light-emitting device by transitioning from a standard p-n junction electroluminescence mechanism to a beam-induced luminescence mechanism. This parameter change allows the device to operate efficiently in the ultraviolet wavelength range by using high-energy electron beams to generate electron-hole pairs directly in the quantum well structure, bypassing the need for p-type layers which become increasingly difficult to form at higher bandgap energies
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 eliminates the efficiency issues associated with p-type semiconductor layers, achieving high brightness and efficiency in ultraviolet light emission by directly forming electron-hole pairs in the active layer, thereby overcoming the limitations of conventional ultraviolet light emitting diodes.
Implementation Method 1
an electron beam generator that generates an electron beam due to an applied voltage
Implementation Method 2
generating ultraviolet light by recombination of electron-hole pairs generated due to collisions of the electron beam
Implementation Method 3
light is emitted from recombination thereof. This is an effect of quantum confinement
Data Source
AI summary
An ultraviolet light emitting device without the use of a p-type semiconductor layer is described. For generating ultraviolet light, an electron beam generator is provided, and an electron beam generated in the electron beam generator is guided to an active layer of an ultraviolet light generator. In the active layer, the electron beam is collided, and electron-hole pairs generated by the collisions are confined in well layers due to barrier layers of the active layer. The confined electrons and holes generate ultraviolet light through recombination.