Solar Cell Graded Crystallization for Lower Contact Resistance
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Solution Overview
Problem
Current transmission resistance in heterojunction solar cells remains high, impacting their performance, despite efforts to improve the contact structure between the metal electrode and transparent conductive film layer.
Innovation Solution
A solar cell design with a semiconductor layer that includes regions of varying crystallization degrees, achieved through laser processing, where a higher crystallization degree is formed away from the surface, reducing contact resistance and allowing for thicker intrinsic silicon layers, thereby improving passivation effects and reducing energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the contact structure between metal electrode and transparent conductive film layer is improved (e.g., adding seed layers or using alloy materials), then adherence is improved, but current transmission resistance remains high
Solution Approach 1:
The patent applies local quality by creating different crystallization degrees in different regions of the semiconductor layer. The first structural region (closer to the surface) has lower crystallization degree for good adherence, while the second structural region (deeper) has higher crystallization degree for low current transmission resistance. This spatial differentiation of material properties resolves the contradiction between adherence and current transmission.
Solution Approach 2:
The patent changes the crystallization degree parameter of the semiconductor layer to resolve the contradiction. By controlling the crystallization degree to vary through the layer thickness (lower near surface, higher deeper), the material achieves both good adherence (via lower crystallization degree) and low current transmission resistance (via higher crystallization degree), without needing additional seed layers or alloy materials.
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 crystallization of the semiconductor layer reduces contact resistance and enhances current collection efficiency, achieving improved performance and efficiency of the solar cell with a simple addition to the manufacturing process.
Implementation Method 1
processing the semiconductor layer by using a first laser, to increase a crystallization degree of at least a part of the semiconductor layer
Implementation Method 2
increase a crystallization degree of at least a part of the semiconductor layer to form a crystallization zone
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
The present application provides a solar cell and a manufacturing method therefor, and pertains to the field of semiconductor device technologies. The solar cell includes a silicon substrate and a semiconductor layer. The silicon substrate includes a first surface and a second surface that are opposite to each other. The semiconductor layer is located on the first surface. The first semiconductor layer includes a second structural region and a first structural region. A crystallization degree of the first structural region is higher than a crystallization degree of the second structural region. The second structural region is closer to the first surface than the first structural region. The first semiconductor layer includes at least one of amorphous silicon, nanocrystalline silicon, or microcrystalline silicon. The semiconductor layer in the present application has a crystalline structure. This can reduce a contact resistance between the semiconductor layer and a conductive material layer, so that a current transmission characteristic is improved, energy consumption in a current collection process is reduced, and efficiency of the solar cell is improved.