Impact of CNx Layer Thickness on the Performance of c-Si Solar Cells: Experimental and PC1D Simulation Study

This study aims to investigate the application of amorphous carbon nitride (CNx) as an alternative anti-reflection coating (ARC) to crystalline silicon solar cells. The CNx films were deposited by reactive RF magnetron sputtering. The measured optical constants were used as input parameters in the PC1D program to simulate the photovoltaic performance of the solar cells. The impact of various refractive indexes and the thickness of the CNx coating as ARC were investigated. Findings revealed that the average reflectance was reduced by 64% using the CNx coating in the 300–1300 nm wavelength range. At the optimum thickness of 85 nm, the power conversion efficiency has increased by 57% compared with the bare silicon solar cell. The results confirm that the contribution to efficiency improvement comes from the gain in short circuit current density rather than the increment in open-circuit voltage. Results also show that the fill factor has an insignificant contribution to efficiency improvement. The external quantum efficiency (EQE) for coating thicknesses between 70 and 90 nm increased by 69% at a wavelength of 600 nm. The present simulation study confirmed that the application of CNx coating is a potential candidate as ARC material for efficient c-Si solar cells.