Characterization of amorphous multilayered ZnO-SnO{sub 2} heterostructure thin films and their field effect electronic properties

Multilayered ZnO-SnO{sub 2} heterostructure thin films were produced using pulsed laser ablation of pie-shaped ZnO-SnO{sub 2} oxides target, and their structural and field effect electronic transport properties were investigated as a function of the thickness of the ZnO and SnO{sub 2} layers. The films have an amorphous multilayered heterostructure composed of the periodic stacking of the ZnO and SnO{sub 2} layers. The field effect electronic properties of amorphous multilayered ZnO-SnO{sub 2} heterostructure thin film transistors (TFTs) are highly dependent on the thickness of the ZnO and SnO{sub 2} layers. The highest electron mobility of 37 cm{sup 2}/V s, a low subthreshold swing of a 0.19 V/decade, a threshold voltage of 0.13 V, and a high drain current on-to-off ratio of ∼10{sup 10} obtained for the amorphous multilayered ZnO(1.5 nm)-SnO{sub 2}(1.5 nm) heterostructure TFTs. These results are presumed to be due to the unique electronic structure of an amorphous multilayered ZnO-SnO{sub 2} heterostructure film consisting of ZnO, SnO{sub 2}, and ZnO-SnO{sub 2} interface layers.