Mechanisms of ZnO buffer layer in bottom gate ZnO:Al transparent thin film transistors

► The ZnO:Al TTFTs inserted ZnO buffer layer were deposited using a RF magnetron cosputter system. ► Better crystalline quality of the ZnO:Al channel layer was obtained by inserting the ZnO buffer layer. ► The improvement of electronic characteristics is attributed to by using the releasing functions of the inserted ZnO buffer layer.