a method of fabricating an active layer thin film by a metal - chalcogenide precursor solution is provided , including the steps of : synthesizing a metal - chalcogenide precursor containing benzyl or benzyl derivative ; dissolving the precursor in a solvent to produce a precursor solution , wherein a chalcogen element or compound can be added to the precursor solution to adjust the molar ratio of metal ion to chalcogen ; and then applying the precursor solution onto a substrate in a specific coating manner , to form a film of the metal - chalcogenide after a curing process . thereby , the existing method wherein an amorphous silicon active layer film is fabricated by plasma enhanced chemical vapor deposition is replaced