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An international research group has used a new porosification technique to build gallium arsenide (GaAs) solar cells that allow germanium films to be recovered. The new cell has achieved an efficiency that is reportedly in line with that of other GaAs photovoltaic devices, but can be produced at a lower cost thanks to the reuse of germanium.
A Belgian-Canadian research team claims to have found a way to develop gallium arsenide (GaAs) solar cells at a lower cost, while maintaining high power conversion efficiencies.
The scientists claim to have grown the cell on removable germanium (Ge) films, allowing the Ge to be reused in other applications, thus reducing production costs. “By ingeniously creating a weak layer between the epitaxial layers and the germanium substrate, we have discovered the possibility of reusing germanium, which represents a significant reduction in both the environmental impact and the production costs of optoelectronic devices,” he told pv magazine Sherbrooke professor Maxime Darnon.
In the article “ High-efficiency GaAs solar cells grown on porous germanium substrate with PEELER technology ,” published in RRL Solar , the research team explains that, To create this weak layer, he used the so-called PEELER technique, a novel electrochemical porosification technique originally used for silicon wafers.
“The versatility of the PEELER process goes far beyond traditional solar cell technology,” says Darnon. From its foundational application in the production of high-efficiency solar cells that redefine industry standards to the creation of lightweight and adaptable solar solutions, PEELER opens the doors to endless possibilities.” Demonstrated with a single junction solar cell, the concept is applicable to multijunction solar cells. It is perfectly suited for space applications where weight and efficiency are paramount. Furthermore, the process finds its application in concentrated photovoltaics, optimizing energy capture in concentrated sunlight environments.”
Using metal-organic chemical vapor deposition (MOCVD), the researchers fabricated a 1 mm2 front-contact GaAs photovoltaic device based on a Ge substrate, the weak Ge layer, an epitaxial Ge layer, the GaAs absorber, a top contact made of nickel (Ni), Ge and gold (Au), and a contact layer.
The champion device built with this architecture achieved a power conversion efficiency of 23.1%, an open circuit voltage of 1.012 V, a short circuit current density of 26.28 mA/cm2, and a fill factor of 81. 98%.
“The demonstrated performance of single-junction GaAs PV cells on porous 100mm Ge wafers not only matches but exceeds that of next-generation GaAs solar cells fabricated on detachable substrate, demonstrating the transformative potential of cultivation.” of high-efficiency optoelectronic devices on detachable Ge films,” stated Darnon.
According to the researchers, the experiment also demonstrated the compatibility of the porous structure with the MOCVD growth technique, confirming the industrial potential of the proposed method.
The research group consisted of scientists from the University of Sherbrooke (Canada), the Canadian energy project developer Saint-Augustin Canada Electric Inc. and the Belgian germanium materials supplier Umicore Electro-Optic Materials. |
