Researchers from the Universidad de Cádiz, Universidad Autónoma de Madrid, and CNRS have published a study in the journal Solar Energy Materials and Solar Cells, exploring ways to improve the efficiency of solar cells made from AlxIn1-xN (Aluminum Indium Nitride) and silicon (Si) heterojunctions.
The team, led by M. Sun and including R. G. Cornejo, M. de la Mata, S. I. Molina, B. Damilano, S. Valdueza-Felip, and F. B. Naranjo, focused on the impact of an optimized amorphous silicon (a-Si) buffer layer on the performance of these solar cells. They varied the aluminum content in the AlInN layer from 0% to 55% and found that the a-Si buffer layer improved the structural quality of the AlInN layer, as evidenced by reduced full width at half maximum values in X-ray diffraction rocking curves around the AlInN (0002) peak. Atomic force microscopy revealed that the buffer layer did not alter the surface roughness.
The researchers demonstrated that the a-Si buffer enhanced the conversion efficiency of the solar cells under AM1.5G illumination from 3.3% to 3.9% for devices with 35% aluminum. They also found that the device with 22% aluminum showed the best photovoltaic performance, with a conversion efficiency of 4.1%, an open-circuit voltage (VOC) of 0.42 V, a short-circuit current density (JSC) of 15.4 mA/cm2, and a fill factor (FF) of 63.3%. However, performance declined for aluminum contents above 36% due to increased resistivity and reduced carrier concentration.
This study highlights the critical role of the novel a-Si buffer layer developed by RF-sputtering and the aluminum content in optimizing AlInN/Si heterojunction solar cell performance. The findings suggest that by carefully controlling these factors, it may be possible to improve the efficiency of these types of solar cells, potentially making them more viable for large-scale energy production. The practical applications for the energy sector include more efficient solar panels that could help increase the adoption of solar energy and reduce reliance on fossil fuels.
This article is based on research available at arXiv.