Porous-silicon coatings for photovoltaic devices

Summary Porous silicon was formed on multicrystalline Si substrates by stain etching in aqueous HF/HNO₃ solutions. In this work optical and electrical properties of the resulting films are discussed as a function of process parameters. Porous-Si films have been shown to be able to reduce surface reflectance to 3% in 350–700 nm wavelength range and their application in anti-reflection coating of photovoltaic solar cells has been demonstrated, obtaining (10×10) cm² multicrystalline Si solar cells with efficiency approaching 12% under standard AM 1.5 simulated sunlight. Paper presented at the III INSEL (Incontro Nazionale sul Silicio Emettitore di Luce), Torino, 12–13 October 1995.