NOVELTY - The system (10) has a set of inner electrodes (14) comprising an open-ended carbon nanotubes array. A first collecting electrode (16) is placed on an outside surface of a first P-N junction cell (12). A second collecting electrode (18) is formed on an outside surface of another junction cell. A photoreceptive surface (17) directly receives incident light beams and acts a surface of the system, and is parallel to the straight line. An emitting bottom surface (11) is opposite to the photoreceptive surface and acts as another surface of the system. A reflector is formed on the bottom surface.    USE - System for a solar cell e.g. silicon-based solar cell, gallium arsenide solar cell and organic thin film solar cell.    ADVANTAGE - The carbon nanotube arrays are made by chemical vapor deposition (CVD) process, so that a number of metal particles can remain, the metal particles can be located between the carbon nanotube arrays, and intermediate resistance between the carbon nanotube array and the P-N junction cells can be reduced so as to enhance photoelectric conversion efficiency of the system. The carbon nanotube arrays are extended from a surface of the P-N junction cell to another surface of the other P-N junction cell adjacent to the former P-N junction cell along axial direction of the carbon nanotubes, so that current is conductive along the axial direction of the carbon nanotubes, and resistance of the carbon nanotubes is reduced so as to reduce inner resistance of a solar cell. The carbon nanotube array is formed on a surface of a P-N junction cell preform, so that bonding force between the carbon nanotube array and the P-N junction cell is strong, and the solar cell is obtained by laminating the P-N junction cell structures.    DETAILED DESCRIPTION - The inner electrode is made of a carbon nanotube composite material.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a method for making a solar cell system.    Solar cell system (10)    Emitting bottom surface (11)    P-N junction cell (12)    Inner electrodes (14)    Collecting electrodes (16, 18)    Photoreceptive surface (17)