Solution-processed ZnO thin-film transistors codoped with Na and F

Abstract

Na and F codoping was utilized to realize high-performance ZnO thin-film transistors derived from sol–gel solution process. The effect of NaF doping concentration on the electrical properties of ZnO thin-film transistors annealed at 350 °C was investigated. Films with 10 at.% doping exhibited excellent performance with an average mobility of 70.98 cm2 V−1 s−1 and a high Ion/Ioff ratio on the order of 106. The X-ray photon spectroscopy exhibited oxygen bound with oxide lattice with and without vacancy related peak position shifted towards lower energy side when doped at 10 at.% and did not show the hydroxyl group on the NaF doped ZnO surface which indicates the improved performance of the thin-film transistors devices. The electrical performance of the devices also changed considerably as the thickness of the NaF-doped ZnO layer increased. Increasing the grain size and realizing a smooth surface morphology by varying the NaF concentration were found to enhance the thin-film transistors mobility.