CdSeTe Photovoltaic Layering to Limit Window Layer Interdiffusion
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Solution Overview
Problem
The challenge in photovoltaic device manufacturing is to maintain an efficient p-n junction while avoiding degradation of the window layer during aggressive activation steps, which can occur due to interdiffusion between semiconductor layers, leading to reduced performance and efficiency.
Innovation Solution
Incorporating a graded selenium composition in the absorber layer through a multi-step process involving CdSe/CdTe layers, where a CdSe seed layer serves as a Se source, allowing for a smooth Se profile and reducing interdiffusion, thereby maintaining the integrity of the window layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aggressive activation steps are used to improve p-n junction efficiency, then junction efficiency is improved, but window layer degradation occurs due to interdiffusion
Solution Approach 1:
A buffer layer is introduced between the window layer and the absorber layer to act as an intermediary that prevents direct interdiffusion between these two layers during aggressive activation steps. This buffer layer allows the activation process to proceed effectively for p-n junction formation while protecting the window layer from degradation by blocking the diffusion path of atoms between the window layer and absorber layer.
2Use of energy by moving object
If the window layer is made thinner to allow maximum light transmission, then photon absorption is improved, but the p-n junction becomes less robust
Solution Approach 1:
The buffer layer serves as a mediator that enables the window layer to be made thinner for improved light transmission while still maintaining a robust p-n junction. The buffer layer provides additional interface area and structural support that compensates for the reduced thickness of the window layer, ensuring the junction remains reliable even with enhanced optical properties.
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 enhances the efficiency of the p-n junction by minimizing interdiffusion and maintaining the window layer's integrity, resulting in improved photon absorption and reduced recombination, thus increasing the overall device performance.
Implementation Method 1
avoiding degradation of the window layer during aggressive activation steps, which can occur due to interdiffusion between semiconductor layers
Implementation Method 2
A photovoltaic structure generates electrical power by converting light into direct current electricity using semiconductor materials that exhibit the photovoltaic effect
Data Source
AI summary
A photovoltaic device includes a substrate structure and at least one Se-containing layer, such as a CdSeTe layer. A process for manufacturing the photovoltaic device includes forming the CdSeTe layer over a substrate by at least one of sputtering, evaporation deposition, CVD, chemical bath deposition process, and vapor transport deposition process. The process can also include controlling a thickness range of the Se-containing layer.