Thin film transistor, method for manufacturing thereof, array substrate and display device

A method for manufacturing a thin film transistor, comprising:

• forming a nanowire active layer on one side of a base substrate;
• forming a conductive protective layer on one side of the nanowire active layer away from the base substrate;
• forming an insulating layer on one side of the protective layer away from the nanowire active layer;
• forming a first via hole exposing a first region of the protective layer and a second via hole exposing a second region of the protective layer by etching the insulating layer using a dry etching process, wherein the first region and the second region are not overlapped with each other;
• and
• forming a source-drain layer on one side of the insulating layer away from the protective layer, wherein the source-drain layer comprises a first electrode and a second electrode, the first electrode is electrically conducted with the nanowire active layer through the first via hole, and the second electrode is electrically conducted with the nanowire active layer through the second via hole.