Crystalline Silicon Solar Cells with Two Different Metals

We propose crystalline silicon solar cells with Al and Au metals. P-type substrates were coated with 100-nm-thick thermally grown SiO2 layers. The top SiO2 layer was thinned to about 1.5 nm. Stripes of Al and Au were formed with a gap of 0.29 mm on the top surface in order to cause an internal built-in potential in silicon because of the difference between their work functions. Solar cell characteristics were observed by halogen lamp illumination at 21.7 mW/cm2. The short-circuit current density, open-circuit voltage, and fill factor were 5.8 mA/cm2, 0.49 V, and 0.57. The conversion efficiency was 7.5%. Photo-induced holes and electrons flowed into Au and Al electrodes, respectively, by the tunneling effect.