NREL、太陽電池をより安くするために音波をテストにかける(NREL Puts Sound Waves to Test in Making Solar Cells Cheaper)


2023-07-19 米国国立再生可能エネルギー研究所(NREL)



音響的にスポーリングされたGaAs基板上に成長したGaAs太陽電池、27%の効率 GaAs solar cells grown on acoustically spalled GaAs substrates with 27% efficiency

Kevin L. Schulte  Steve W. Johnston, Anna K. Braun, Jacob T. Boyer, Anica N. Neumann, William E. McMahon, Michelle Young, Pablo Guimerá Coll, Mariana I. Bertoni, Emily L. Warren, Myles A. Steiner
Joule  Published: June 19, 2023

Context & scale

III–V solar cells offer the highest solar photovoltaic conversion efficiencies of any technology, but high manufacturing costs limit their use in terrestrial applications. Roughly one-third of the cost of a III–V solar cell comes from the single-crystalline substrate on which it is grown. Acoustic spalling is a new process that enables the rapid cleavage of III–V devices from their parent substrates, potentially enabling substrate reuse if high-efficiency devices can be grown on previously spalled substrates.

In this work, we study the vapor growth of GaAs solar cells on previously spalled GaAs substrates and develop an understanding of how the spalled surface affects subsequent device growth and performance. We develop a GaAs device grown on a previously spalled substrate with 27% efficiency, which compares favorably to GaAs efficiencies obtained on any III–V substrate. These results highlight the potential of acoustic spalling as a viable substrate reuse technology.


Acoustic spalling presents a potentially low-cost reuse pathway for III–V epitaxial growth substrates via exfoliation of device layers with recovery and reuse of the substrate. However, surface features formed during spalling can reduce the performance of subsequently grown devices. We develop an understanding of how the surface morphology of acoustically spalled substrates affects GaAs solar cell performance and develop strategies to mitigate these impacts. We demonstrate that minor planarization of the surface by wet chemical etching and/or epitaxial growth, or the redesign of the device structure to thicken critical layers, prevents performance degradation. Using these strategies, we demonstrate a 0.25 cm2 single-junction GaAs device with 26.9% ± 0.2% photovoltaic conversion efficiency under the AM1.5G spectrum grown on an acoustically spalled substrate. These results enable the growth of high-performance III–V devices on non-traditional substrates with the potential for significantly reduced device costs.