Norihiro Terada

High-quality polycrystalline silicon thin film prepared by a solid phase crystallization method

Abstract We succeeded in fabricating high-quality polycrystalline silicon (poly-Si) thin films with no boundary from the bottom surface to the top, and achieved an extremely high electron mobility of 808 cm2/V s by a solid phase crystallization (SPC) method. This film was obtained by using a new nucleation layer with 1000 A wide single-crystalline grains embedded in a matrix of amorphous tissue. A poly-Si thin-film solar cell fabricated using this film as an active layer demonstrated a total area conversion efficiency of 9.2% (active area efficiency: 9.7%), which is the worlds highest value for crystalline silicon solar cells fabricated below 600°C on metal substrates.

Numerical approach for high-efficiency a-Si solar cells

Abstract We have developed the first precise numerical simulator for thin-film solar cells with two-dimensional structures, such as a submicron textured a-Si solar cell. Conventional simulators for thin-film solar cells were all one-dimensional, which made precise simulation of the behavior of light and carrier transport in the cell impossible. Using the 2D simulator, guidelines for cell design, including textured structures, were obtained. One proposal to increase the conversion efficiency of the textured a-Si single-junction solar cell is to make the texture period longer than the film thickness.