Sputtered Non-Hydrogenated Amorphous Silicon as Alternative Absorber for Silicon Photovoltaic Technology

Abstract

Non-hydrogenated amorphous-silicon films were deposited on glass substrates by Radio

Frequency magnetron sputtering with the aim of being used as precursor of a low-cost absorber

to replace the conventional silicon absorber in solar cells. Two Serie of samples were deposited

varying the substrate temperature and the working gas pressure, ranged from 0.7 to 4.5 Pa. The first

Serie was deposited at room temperature, and the second one, at 325 ◦C. Relatively high deposition

rates above 10 Å/s were reached by varying both deposition temperature and working Argon gas

pressure to ensure high manufacturing rates. After deposition, the precursor films were treated

with a continuous-wave diode laser to achieve a crystallized material considered as the alternative

light absorber. Firstly, the structural and optical properties of non-hydrogenated amorphous silicon

precursor films were investigated by Raman spectroscopy, atomic force microscopy, X-ray diffraction,

reflectance, and transmittance, respectively. Structural changes were observed in the as-deposited

films at room temperature, suggesting an orderly structure within an amorphous silicon matrix;

meanwhile, the films deposited at higher temperature pointed out an amorphous structure. Lastly,

the effect of the precursor material’s deposition conditions, and the laser parameters used in the

crystallization process on the quality and properties of the subsequent crystallized material was

evaluated. The results showed a strong influence of deposition conditions used in the amorphous

silicon precursor