High Performance Amorphous Multilayered ZnO-SnO2 Heterostructure Thin-Film Transistors: Fabrication and Characteristics

Multilayered ZnO-SnO2 heterostructure thin films consisting of ZnO and SnO2 layers are produced by alternating the pulsed laser ablation of ZnO and SnO2 targets, and their structural and field-effect electronic transport properties are investigated as a function of the thickness of the ZnO and SnO2 layers. The performance parameters of amorphous multilayered ZnO-SnO2 heterostructure thin-film transistors (TFTs) are highly dependent on the thickness of the ZnO and SnO2 layers. A highest electron mobility of 43 cm2/V·s, a low subthreshold swing of a 0.22 V/dec, a threshold voltage of 1 V, and a high drain current on-to-off ratio of 1010 are obtained for the amorphous multilayered ZnO(1.5 nm)-SnO2(1.5 nm) heterostructure TFTs, which is adequate for the operation of next-generation microelectronic devices. These results are presumed to be due to the unique electronic structure of amorphous multilayered ZnO-SnO2 heterostructure film consisting of ZnO, SnO2, and ZnO-SnO2 interface layers.