Hisao Kumabe

Ten-thousand-hour operation of crank transverse-junction-stripe lasers grown by metal-organic chemical vapor deposition

For over 10 000 h, crank transverse-junction-stripe (TJS) laser diodes, grown by metal-organic chemical vapor deposition (MOCVD) maintain low and quite stable operating currents in the automatic-power-control aging with output power of 5 mW/facet at 55°C and 70°C. These MO-CVD lasers have excellent initial characteristics and small distributions of the characteristics. The reason for this excellent result is discussed in relation to the crystalline quality and the uniform growth of MO-CVD wafers.

Thickness dependence of defect density in thin film silicon formed on insulator polycrystalline by zone-melting recrystallization [solar cells]

Formation technique of high quality thin film polycrystalline Si on insulator by zone-melting recrystallization (ZMR) was investigated for use in Si solar cell applications. Varying the thickness of polycrystalline Si of ZMR samples, thickness dependence of defect density in ZMR-Si films was studied. It was found that defect density of ZMR-Si film was strongly affected by thickness of polycrystalline Si. By thinning the polycrystalline Si film, defect density of ZMR-Si film was reduced to 3/spl times/10/sup 6//cm/sup 2/ without lowering scanning speed at ZMR process.

Characterization of thickness dependence on defect density and hydrogen passivation for thin film polycrystalline silicon solar cells

Thickness dependence on defect density and hydrogen passivation for thin film polycrystalline silicon solar cells fabricated by the zone-melting recrystallization (ZMR) technique are experimentally investigated. We confirmed that thinning of the active layer is available for increasing Voc for the cells with relatively high defect density (1/spl times/10/sup 6/-1/spl times/10/sup 7/ cm/sup -2/). At the same time, it was clarified that the effectiveness of hydrogen passivation is strongly dependent on the total amount of 3-dimensionally distributed defect in the active layer. Light-induced degradation phenomenon of hydrogen passivated cells was also investigated under the conditions of AM1.5, 125 mW/cm/sup 2/, and 48/spl deg/C. Significant degradation was not observed over 300 hours such as in hydrogenated amorphous silicon solar cells.