Research on the fabrication and anti-reflection performance of diamond-like carbon films

Abstract

In this work, a radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) system has been employed to fabricate diamond-like carbon (DLC) films for the application in crystalline silicon solar cells. The morphological, structural and optical properties of the synthesised DLC films were investigated under different deposition times, different plasma discharge powers, different CH4 flow rates, and different substrate temperatures, respectively. It is shown that, when the plasma discharge power was 100 W, the CH4 flow rate was 60 sccm, and the substrate temperature was 100 °C, the synthesised DLC film features a high transmittance of 95%, a low surface reflectivity of approximately 14%, a wide optical band gap of 2.6 eV, as well as a uniform and dense texture. Subsequently, the DLC films with different thicknesses were grown on the surface of crystalline silicon solar cells as anti-reflection coatings. The solar cell current-voltage characteristic testing system was used to investigate the change of solar cell performance parameters, i.e., Jsc, Voc, FF and η. After the growth of a DLC film with a deposition time of 20 min on the surface of a crystalline silicon solar cell, the photovoltaic conversion efficiency of the solar cell increases from 4.12% to 5.2%. This work demonstrates that the DLC film has a promising application potential as an anti-reflection layer in crystalline silicon solar cells.