Compound thin film solar cell and method for manufacturing the same

A method for manufacturing a compound thin film solar cell, comprising the steps of:

• forming a back electrode on a substrate;
• forming a light-absorbing layer which includes a compound semiconductor thin film on the back electrode;
• forming a buffer layer on the light-absorbing layer;
• forming a semi-insulating layer on the buffer layer;
• forming a transparent electrode layer on the semi-insulating layer;
• forming a lead-out electrode on the back electrode;
• forming a lead-out electrode on the transparent electrode layer;
• and
• forming an interfacial interlayer at an interface between the back electrode and the light-absorbing layer, wherein
• the light-absorbing layer is a semiconductor thin film which contains Cu, an element A (A is at least one element selected from a group consisting of Al, In and Ga) and an element X (X is at least one element selected from a group consisting of S, Se and Te), and has a chalcopyrite crystal structure,
• a method for forming the light-absorbing layer is a sputtering method in the step of forming the light-absorbing layer, and
• a method for forming the interfacial interlayer is heating treatment in the step of forming the interfacial interlayer.

A method for manufacturing a compound thin film solar cell, comprising the steps of:

• forming a back electrode on a substrate;
• forming a light-absorbing layer which includes a compound semiconductor thin film on the back electrode;
• forming a crystal phase of CucAdX1-c-d (A is at least one element selected from a group consisting of Al, In and Ga, X is at least one element selected from a group consisting of S, Se and Te, c is not larger than 0.1, and d is not smaller than 0.1, or c+d is not smaller than 0.9) at an interface between the back electrode and the light-absorbing layer;
• forming a buffer layer on the light-absorbing layer;
• forming a semi-insulating layer on the buffer layer;
• forming a transparent electrode layer on the semi-insulating layer;
• forming a lead-out electrode on the back electrode;
• forming a lead-out electrode on the transparent electrode layer;
• and
• forming an interfacial interlayer at the interface between the back electrode and the light-absorbing layer.