| 摘要 |
PURPOSE:To prevent loss of an optical carrier formed in the vicinity of a back surface electrode, by providing at least a double-layer structure for the back surface electrode, and making the work function of the back surface electrode layer, which is contacted with a p type layer, to be 4.5eV or more. CONSTITUTION:In a photoelectromotive force element, in which a semiconductor layer comprises an amorphous semiconductor and especially the light incident side is an n type layer, a first back surface electrode layer 25 has a work function of 4.5eV or more. As a metal material suitable for the element, e.g., gold is used. As a second back surface electrode 25b, e.g., silver or aluminum, whose light reflectivity with respect to light having a long wavelength is larger than that of the first back surface electrode layer 25a, is used. Since the work function of a p type layer 24 is the same as that of the first surface electrode layer 25a, a barrier against holes generated at their boundary is small, and the light carrier can be effectively collected on the back surface electrode. The light having the long wavelength, which is included in the incident light, is hard to be absorbed in the semiconductor layer. The long wavelength light, which is transmitted through the first back surface electrode layer 25a, is reflected by the second back surface electrode layer 25b and returned into the semiconductor layer. Said light contributes to the generation of the light carrier. |
