Laminated structure for CIS based solar cell, and integrated structure and manufacturing method for CIS based thin-film solar cell
This invention aims to provide a laminated structure and an integrated structure of a high production efficiency for a CIS based thin-film solar cell, which can produce a high-resistance buffer layer of the CIS based thin-film solar cell efficiently on a series of production lines and which needs no treatment of wastes or the like, and a manufacturing method for the structures. The CIS based thin-film solar cell includes a back electrode, a p-type CIS based light absorbing layer, a high-resistance buffer layer and an n-type transparent conductive film laminated in this order. The high-resistance buffer layer and the n-type transparent conductive film are formed of thin films of a zinc oxide group. The buffer layer contacts the p-type CIS based light absorbing layer directly, and has a resistivity of 500Ω·cm or higher.
1. A method for manufacturing a CIS based thin-film solar cell, comprising the steps of:
making a back electrode on a substrate selected from the group consisting of glass and metal;
forming a p-type CIS based light absorbing layer on the back electrode;
forming a buffer layer formed of a thin film of a zinc oxide group directly on the p-type CIS based light absorbing layer; and
forming an n-type transparent conductive film formed of the thin film of a zinc oxide group on the buffer layer,
wherein the buffer layer forming step is performed by an MOCVD method, and
a substrate temperature of the buffer layer forming step is 190 to 300° C. which is higher than the substrate temperature at the time of forming the n-type transparent conductive film for keeping a high resistivity of the buffer layer which is 500Ω·cm or higher by avoiding diffusion of dopant from the n-type transparent conductive film to the buffer layer.
2. The method for manufacturing a CIS based thin-film solar cell according to claim 1 , wherein the n-type transparent conductive film is formed by the MOCVD method.
3. The method for manufacturing a CIS based thin-film solar cell according to claim 1 , wherein a film forming rate of the buffer layer is 15 nm per minute or higher.
4. The method for manufacturing a CIS based thin-film solar cell according to claim 1 ,
the n-type transparent conductive film is an electrode and contains dopant.