Solar Cell Impurity Region Design for Carrier Recombination
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Solution Overview
Problem
Current solar cells face challenges in enhancing power generation characteristics due to carrier recombination and conductivity issues at the semiconductor surfaces, which affect the efficiency of sunlight conversion into electric power.
Innovation Solution
A solar cell design incorporating a semiconductor substrate with specific impurity regions of varying concentrations on both surfaces, including a first impurity region, a second impurity region with higher concentration, and a third impurity region, to optimize the surface electric-field effect and prevent conductivity decrease, thereby improving power generation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impurity regions are added to the semiconductor substrate to improve surface conductivity, then power generation characteristics are improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating impurity regions with different concentrations at specific locations within the semiconductor substrate. The first impurity region is formed at the interface with the first semiconductor layer, the second impurity region is formed at the interface with the second semiconductor layer, and a third impurity region is formed at a intermediate position. Each region has a different impurity concentration optimized for its local function, thereby improving surface conductivity and power generation characteristics without uniformly complicating the entire device structure.
Solution Approach 2:
The patent segments the semiconductor substrate into distinct impurity regions to address different functional requirements. By dividing the substrate into multiple zones with different impurity concentrations - a first impurity region near the first semiconductor layer, a second impurity region near the second semiconductor layer, and a third impurity region in between - the design allows each segment to optimize local electrical properties, reducing carrier recombination at interfaces while maintaining overall device functionality.
2Reliability
If impurity concentration is increased at semiconductor surfaces to prevent conductivity decrease, then carrier recombination is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the impurity concentration across different regions of the semiconductor substrate. The first impurity region has a first concentration, the second impurity region has a second concentration, and the third impurity region has a third concentration, where these parameters are optimized to reduce carrier recombination. This gradual parameter variation allows for better control of electrical properties while managing manufacturing precision requirements through defined concentration gradients rather than abrupt changes.
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 proposed design effectively reduces carrier recombination and maintains conductivity, leading to enhanced power generation characteristics in solar cells and modules by optimizing the impurity concentration profiles across the semiconductor substrate surfaces.
Implementation Method 1
optimize the surface electric-field effect and prevent conductivity decrease
Implementation Method 2
reduces carrier recombination
Implementation Method 3
the solar cell can directly convert clean and unlimited sunlight into electric power
Data Source
AI summary
A solar cell includes: a semiconductor substrate which includes a first principal surface and a second principal surface; a first semiconductor layer of the first conductivity type disposed above the first principal surface; and a second semiconductor layer of a second conductivity type disposed below the second principal surface. The semiconductor substrate includes: a first impurity region of the first conductivity type; a second impurity region of the first conductivity type disposed between the first impurity region and the first semiconductor layer; and a third impurity region of the first conductivity type disposed between the first impurity region and the second semiconductor layer. A concentration of an impurity in the second impurity region is higher than a concentration of the impurity in the third impurity region, and the concentration of the impurity in the third impurity region is higher than a concentration of the impurity in the first impurity region.