The effect of the native silicon dioxide interfacial layer on photovoltaic characteristics of gold/p-type amorphous boron carbon thin film alloy/silicon dioxide/n-type silicon/aluminum solar cells

• a-BC/SiO2/n-Si solar cells are prepared by a reactive sputtering system.
• The SiO2 layer improves photovoltaic properties of Au/a-BC/SiO2/n-Si/Al solar cells.
• The Au/a-BC/SiO2/n-Si/Al solar cell has a fill factor of 0.934 at 200 W/m2.

The effect of the thin native silicon dioxide (SiO2) interfacial layer on the photovoltaic characteristics of gold/p-type amorphous boron carbon thin film alloy/silicon dioxide/n-type silicon/aluminum (Au/a-BC/SiO2/n-Si/Al) solar cells is investigated. a-BC thin film alloy was deposited on n-Si substrate with an SiO2 layer using a reactive sputtering system. The front and back surfaces of this a-BC/SiO2/n-Si solar cell were covered with Au and Al electrodes, respectively. a-BC thin film alloys and Au/a-BC/SiO2/n-Si/Al solar cells were annealed at 623 K in an atmosphere of argon. Raman spectra and X-ray photoelectron spectroscopy results show that the a-BC thin film alloy has a D band and a G band and the boron/carbon ratio is 12.4%. The optical band gap and electrical resistivity of the a-BC thin film alloy are 1.90 eV and 7.73×104 Ω m, respectively. Under illumination at 1000 W/m2, the Au/a-BC/SiO2/n-Si/Al solar cell exhibits a short-circuit current density, open-circuit voltage, fill factor, and power conversion efficiency of 165 A/m2, 0.22 V, 0.904, and 3.3%, respectively. Remarkably, the Au/a-BC/SiO2/n-Si/Al solar cell has a fill factor of 0.934 at an illumination intensity of 200 W/m2, which exceeds any value obtained to date. The thin SiO2 layer improves the photovoltaic characteristics of Au/a-BC/SiO2/n-Si/Al solar cells, and the reasons for this improvement are discussed herein.