Stacked p-n Junction Capacitor for High-Density Radiation Energy Conversion
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Solution Overview
Problem
Existing capacitors do not efficiently convert radiation energy into electrical energy with high energy density.
Innovation Solution
A stack-type capacitor design comprising cell sheets with a p-n-junction interface, where a second material layer with higher conductivity than the first layer is interposed between a radiation source and the first layer, forming a p-n-junction, and stacked in parallel, with external electrodes connected to the cell sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional single-layer semiconductor structure is used, then the device complexity is low, but the energy density and radiation conversion efficiency are insufficient
Solution Approach 1:
The semiconductor structure is divided into multiple layers including a first semiconductor layer, a second semiconductor layer, and a third semiconductor layer, each with different bandgap energies. This segmentation allows optimized radiation absorption at different depths while maintaining manageable device complexity through modular layer design.
Solution Approach 2:
The invention uses composite semiconductor materials with different bandgap energies arranged in specific layers. The first semiconductor layer has a first bandgap, the second has a second bandgap, and the third has a third bandgap, creating a composite structure that efficiently converts different radiation energies into electrical energy with high energy density.
2Loss of energy
If radiation sources are placed directly adjacent to semiconductor material, then the energy conversion path is short, but carrier recombination loss increases
Solution Approach 1:
The second semiconductor layer with intermediate bandgap energy acts as an intermediary between the first and third semiconductor layers. It facilitates carrier transport while reducing recombination loss by providing a stepped energy transition path, effectively mediating the energy conversion process between high-energy and low-energy regions.
Solution Approach 2:
The invention changes the bandgap energy parameter across different layers, with the first semiconductor layer having a first bandgap, the second having a second bandgap, and the third having a third bandgap. This parameter gradient optimizes carrier generation and transport while minimizing recombination losses at each interface.
3Productivity
If multiple cell sheets are stacked to increase energy density, then the energy density increases, but the manufacturing precision requirements increase
Solution Approach 1:
The capacitor is divided into multiple cell sheets stacked in series, with each cell sheet containing a complete set of three semiconductor layers forming p-n junctions. This segmentation allows independent fabrication and testing of each cell sheet before assembly, reducing overall manufacturing precision requirements while achieving high energy density through stacking.
Solution Approach 2:
The invention transitions from a planar single-layer structure to a three-dimensional stacked configuration of multiple cell sheets. By utilizing the vertical stacking dimension, the energy density increases significantly while the manufacturing precision requirements are managed through standardized cell sheet design and assembly processes.
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
Generates electrical energy with high energy density by efficiently converting radiation energy using metal oxides with high carrier mobility and no energy loss.
Implementation Method 1
Radiation emitted by a radioactive isotope can be absorbed through the surface of a p-n junction in a semiconductor and converted into electrical energy. The radiation generate electron-hole pairs in the space-charge region of the p-n junction semiconductor
Implementation Method 2
a second material layer formed of a material having an electrical conductivity higher than the electrical conductivity of the first material layer
Data Source
Figure 1a
Figure 1b
Figure 1c~1d
AI summary
A stack-type capacitor includes: a plurality of cell sheets that are stacked; and a first external electrode of a first polarity and a second external electrode of a second polarity electrically connected to the plurality of cell sheets. Each of the plurality of cell sheets includes: a first material layer including either a non-conductor or a semiconductor; a second material layer having an electrical conductivity higher than the electrical conductivity of the first material layer and forming an interface with the first material layer; and a radiation source spaced from the interface and located within the first material layer.