Method for producing semiconductor layer, method for producing photoelectric conversion device, and semiconductor starting material

Methods for producing a semiconductor layer and for producing a photoelectric conversion device, semiconductor raw material are disclosed. An embodiment of the method for producing a semiconductor layer includes: forming a film containing a metal element and an oxygen element; generating oxygen gas by heating the film; and forming a semiconductor layer containing a metal chalcogenide from the film by allowing the metal element to react with a chalcogen element. Another embodiment of the method includes forming a lower film containing a metal element; forming an upper film, which contains the metal element and a substance that contains oxygen, on the lower film; generating oxygen gas by heating the substance; and forming a semiconductor layer containing a metal chalcogenide from the lower film and the upper film by allowing a chalcogen element to react with the metal element in the lower film and the upper film.