Photovoltaic Cell Manufacturing Using Silicon Substrate and Buffer Layer
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Solution Overview
Problem
Conventional methods for manufacturing photovoltaic cells using compound semiconductors are costly due to the need for expensive substrates like GaAs or InP, and existing solutions do not effectively reduce production costs while maintaining high efficiency.
Innovation Solution
A photovoltaic cell manufacturing method that uses a silicon substrate with a buffer layer to relax lattice constants, allowing for the growth of compound semiconductor layers without the need for expensive substrates, and involves a process of layer deposition and etching to form multi-junction cells, such as GaInP and GaAs cells, which are then bonded to a support substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If expensive GaAs or InP substrates are used for manufacturing photovoltaic cells, then high energy conversion efficiency is achieved, but manufacturing cost increases significantly
Solution Approach 1:
The patent uses inexpensive silicon substrates instead of expensive GaAs or InP substrates. The silicon substrate serves as a temporary platform during manufacturing that can be discarded or retained based on application requirements, dramatically reducing substrate cost while maintaining photovoltaic cell efficiency
Solution Approach 2:
The patent extracts and removes the expensive GaAs or InP substrate layer from the final product structure. By using silicon as a sacrificial or retained substrate and selectively removing or isolating the compound semiconductor layers, the invention eliminates the need for costly substrates in the final photovoltaic cell structure
2Reliability
If a buffer layer is added to relax lattice constants between Si substrate and compound semiconductor, then dislocation is reduced, but device complexity increases
Solution Approach 1:
The patent introduces a buffer layer as an intermediary structure between the silicon substrate and the compound semiconductor layers. This buffer layer mediates the lattice mismatch by providing a transition zone that relaxes lattice constants progressively, reducing dislocation propagation to the active photovoltaic layers
Solution Approach 2:
The buffer layer changes the lattice constant parameter gradually from the silicon substrate value to the compound semiconductor value. By creating an intermediate lattice constant structure, the patent reduces the abrupt lattice mismatch that would otherwise cause extensive dislocations
3Reliability
If buffer layer is retained in final product, then lattice relaxation is maintained, but manufacturing precision deteriorates due to buffer layer defects
Solution Approach 1:
The patent extracts and removes the buffer layer from the final photovoltaic cell structure after it has served its purpose during manufacturing. By eliminating the buffer layer containing dislocations and defects from the final product, the invention maintains high manufacturing precision and cell quality while the lattice relaxation benefit was already achieved during the growth process
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 method enables the production of high-efficiency photovoltaic cells at a lower cost by eliminating the need for expensive substrates and ensuring high reliability by removing the buffer layer from the final product, resulting in a flexible and lightweight cell with improved energy conversion efficiency.
Implementation Method 1
a buffer layer is provided between the Si substrate and the photovoltaic cell layer for relaxing the lattice constant (performing lattice relaxation), in order to cause the difference in the lattice constant to relax as much as possible in the buffer layer
Implementation Method 2
a multi-junction photovoltaic cell is produced, by which the wavelength range of sunlight is divided among a plurality of photovoltaic cells so that the energy conversion efficiency is increased
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A photovoltaic cell manufacturing method includes depositing a first buffer layer for performing lattice relaxation on a first silicon substrate; depositing a first photoelectric conversion cell on the first buffer layer, the first photoelectric conversion cell being formed with a compound semiconductor including a pn junction, and the first photoelectric conversion cell having a lattice constant that is higher than that of silicon; connecting a support substrate to the first photoelectric conversion cell to form a first layered body; and removing the first buffer layer and the first silicon substrate from the first layered body.