Effect of Mg content on characteristics of amorphous ZnMgSnO thin-film transistors by a combustion solution process

Amorphous zinc–magnesium–tin oxide (a-ZMTO), a new kind of amorphous oxide semiconductors (AOSs), was prepared for fabricating thin-film transistors (TFTs) by a combustion solution process. The prepared ZnMgSnO films have a high amorphous quality with smooth surface, evenly distributed elements, as well as high visible transmittance above 80% with a width of band gap of around 3.12 eV. The effects of Mg content on properties of films and performance of devices were investigated in detail. An appropriate Mg content could efficiently suppress the oxygen vacancy (VO) concentration and make the surface smoother, thereby enhancing the properties of films and performance of related a-ZMTO TFTs. The a-ZMTO TFTs exhibited acceptable performances, with field-effect mobility (μFE) of 0.083 cm2 V−1 S−1, on/off current ratio (Ion/Ioff) of around 3.0 × 104, and threshold voltage (Vth) of 1.42 V. The a-ZMTO films and ZMTO TFTs may offer an option of indium-free AOS materials for future application in transparent electronics.