(JP10012635-A)      The apparatus has a pair of reaction chambers (A,B) formed of multilayer body. The two chambers are connected through an interconnection passage. A vapour source for a VI group element is provided in the second reaction chamber.    A set of heating units are provided on exterior with temperature controllers respectively for the chambers. The specimen is heated in vacuum environment in first chamber for formation of compound layer in second chamber.    ADVANTAGE -   Improves electric conversion efficiency. Saves energy.    (US5935324-A)      An apparatus for forming I-III-VI2 thin films comprises (a) a first reaction space made of carbon and holding an intermediate product for thin film formation; (b) one or more second reaction spaces, each of which is made of carbon and holds a group VI element vapour source; (c) a conduit connecting the first reaction space to the or each second reaction space; and (d) a temperature-controlled heating system positioned outside each reaction space.    Also claimed is a process for forming I-III-VI2 thin films in vacuum using the above apparatus by (i) raising the temperatures in the reaction spaces to that at which a solid solution of the group VI element is produced; (ii) raising the temperature in the second reaction space to above this solid solution temperature so that vapour of the group VI element passes from the second reaction space through the conduit into the first reaction space for forming the group VI element solid solution; and (iii) lowering the temperature in the se cond reaction space before that in the first reaction space so that the group VI element, present within the first reaction space and as an unreacted deposit on the I-III-VI2 thin film surface, returns as vapour through the conduit back into the second reaction space.    USE -   For producing thin films of I-III-VI2 compound semiconductors, e.g. CuInSe2 (CIS), for use in e.g. solar cells.    ADVANTAGE -   The apparatus permits efficient production of good quality I-III-VI2 thin films with less energy and lower costs.    (DE19717565-C2)      An apparatus for forming I-III-VI2 thin films comprises (a) a first reaction space made of carbon and holding an intermediate product for thin film formation; (b) one or more second reaction spaces, each of which is made of carbon and holds a group VI element vapour source; (c) a conduit connecting the first reaction space to the or each second reaction space; and (d) a temperature-controlled heating system positioned outside each reaction space.    Also claimed is a process for forming I-III-VI2 thin films in vacuum using the above apparatus by (i) raising the temperatures in the reaction spaces to that at which a solid solution of the group VI element is produced; (ii) raising the temperature in the second reaction space to above this solid solution temperature so that vapour of the group VI element passes from the second reaction space through the conduit into the first reaction space for forming the group VI element solid solution; and (iii) lowering the temperature in the se cond reaction space before that in the first reaction space so that the group VI element, present within the first reaction space and as an unreacted deposit on the I-III-VI2 thin film surface, returns as vapour through the conduit back into the second reaction space.    USE -   For producing thin films of I-III-VI2 compound semiconductors, e.g. CuInSe2 (CIS), for use in e.g. solar cells.    ADVANTAGE -   The apparatus permits efficient production of good quality I-III-VI2 thin films with less energy and lower costs.