Title :
The effect of superlattice buffer of microcrystalline silicon solar cells
Author :
Ito, Manahu ; Kondo, Michio ; Matsuda, Akihisa
Author_Institution :
Nat. Inst. of Adv. Ind. Sci. & Technol., Japan
Abstract :
In order to improve the open circuit voltage (V/sub oc/) of /spl mu/c-Si:H solar cells, a p/i buffer layer has been studied using a-Si//spl mu/c-Si superlattice structure. Substrate type solar cells were prepared at 140/spl deg/C onto flat substrate with i-layer thickness of 1/spl mu/m. Two kinds of the buffer layer were examined; one is a-Si single layer with a thickness of 2 to 12nm and the other is a-Si//spl mu/c-Si multilayers. By inserting a single 2nm thick a-Si layer, V/sub oc/ increases from 0.472 V to 0.530V and fill factor (FF) increases from 70.5% to 74.3%. Although the short wavelength response decreases slightly, efficiency increases from 6.1% to 6.4%. Furthermore, we examined a-Si//spl mu/c-Si superlattice structure at pi interface and demonstrate /spl mu/c-Si solar cell with FF of 75.3%. These are attributed to reduction of the diode saturation current by the insertion of wide band gap material, which acts as a barrier.
Keywords :
amorphous semiconductors; elemental semiconductors; interface structure; plasma CVD coatings; semiconductor superlattices; semiconductor thin films; silicon; solar cells; /spl mu/c-Si:H solar cells; 0.472 to 0.530 V; 1 micron; 140 degC; 2 to 12 nm; Si; amorphous Si-/spl mu/c Si multilayers; amorphous-Si single layer; diode saturation current reduction; fill factor; flat substrate; microcrystalline silicon solar cells; open circuit voltage; pi interface; plasma CVD coatings; short wavelength response; substrate type solar cells; superlattice buffer; superlattice structure; wide band gap barrier material;
Conference_Titel :
Photovoltaic Energy Conversion, 2003. Proceedings of 3rd World Conference on
Conference_Location :
Osaka, Japan
Print_ISBN :
4-9901816-0-3