High efficiency thin film silicon solar cells prepared by zone-melting recrystallization

A new type of silicon solar cell is demonstrated using chemical vapor deposited silicon thin films on a silicon dioxide layer. In order to improve the crystal quality of the thin films, zone-melting recrystallization (ZMR) is applied and grain boundaries of polycrystalline Si films are passivated with H+. It is found that H+ passivation is quite effective for thin film Si solar cells and ZMR conditions to provide dominant (100) orientation is essential for achieving higher conversion efficiency. This (100) nature is also favorable for making effective light confinement scheme with pyramidal textured surface using anisotropic chemical etching. The conversion efficiency as high as 14.2% for a practical size of 10×10 cm2 is achieved. This is the highest for large area thin film polycrystalline Si solar cells so far.