HYDROGENATION EFFECTS ON N+-P INP SOLAR-CELL

The hydrogenation effects on the solar cell property have been investigated in the sulfur (S) diffused n+ -p solar cell. In the plasma-hydrogenated n+ -p junction at 150-degrees-C for 30 min, the carrier concentration of p-type substrate (Zn doped) decreased by one order of magnitude as the distance from the junction region becomes 0.7 mum. This indicates that the hydrogen passivation by atomic hydrogen is due to the form of the neutral hydrogen-Zn acceptor complex near the junction region. The InP solar cell properties, especially the conversion efficiency and the short circuit current of the solar cell, were remarkably improved by 150-degrees-C hydrogenation. The mechanism for the hydrogen passivation effects on the InP solar cell is also discussed. It is shown that the increase of the solar cell efficiency and short circuit current after hydrogenation may be due to the formation of the n+ -p- -p structure by the hydrogen-defect incorporation and adequate control of the carrier density in the p-type substrate.