Manabu Komoda

Thin film poly-Si solar cells using PECVD and Cat-CVD with light confinement structure by RIE

Poly-Si film prepared by PECVD method showed low ESR spin density of around 1E16/cm3 and poly-Si film prepared by Cat-CVD method showed relatively low ESR spin density of around 1E17/cm3. The cell using PECVD poly-Si film as a photo-active layer showed an intrinsic cell efficiency of 7.75%. Light confinement micro-structure was introduced to the cell applying RIE method to the glass substrate surface and enhancement of Jsc was observed.

Formation of silicon films for solar cells by the Cat-CVD method

Abstract We have investigated the formation of poly-Si photoactive films by the catalytic chemical vapor deposition (Cat-CVD) method. By optimum control of the substrate deposition temperature, poly-Si films with a crystalline fraction higher than 90% and dangling-bond density of 2.5×10 16 cm −3 were obtained at a deposition rate greater than 10 A s −1 . It was also found that the lateral grain size of the poly-Si films increases from 0.1 to 0.5 μm by suppressing chemical transport from the chamber wall.

Thin film poly-Si formation by Cat-CVD method and its application for solar cells

Abstract Poly-Si thin film which has an ESR spin density of 6.9 E16/cm3 was obtained by Cat-CVD with a deposition rate of 5.4 A/s at a relatively high deposition pressure (approx. 30 Pa) with a high hydrogen dilution (SiH4/H2=0.05). The low ESR spin density films were applied to solar cells as a photo-active layer. Although the dark V–I curves of the cell showed diode characteristics, the photo V–I curves showed very small photo-current densities, lower than 0.5 mA/cm2. A large amount of higher order silane molecules at the present high deposition pressure might be one of the causes of this small photo-current density, as well as grain boundary recombination and an incubation layer at the first stage of film deposition.