Room-temperature fabricated thin-film transistors based on compounds with lanthanum and main family element boron

Abstract

For the first time, compounds with lanthanum from the main family element Boron (LaBx) were investigated as an active layer for thin-film transistors (TFTs). Detailed studies showed that the room-temperature fabricated LaBx thin film was in the crystalline state with a relatively narrow optical band gap of 2.28 eV. The atom ration of La/B was related to the working pressure during the sputtering process and the atom ration of La/B increased with the increase of the working pressure, which will result in the freer electrons in the LaBx thin film. LaBx-TFT without any intentionally annealing steps exhibited a saturation mobility of 0.44 cm2·V−1·s−1, which is a subthreshold swing (SS) of 0.26 V/decade and a Ion/Ioff ratio larger than 104. The room-temperature process is attractive for its compatibility with almost all kinds of flexible substrates and the LaBx semiconductor may be a new choice for the channel materials in TFTs.