Fig. 2: Material characterizations of ZnO channel layer.

a SEM image of the ZnO TFT channel and cross-section schematic. b TEM image of the ZnO TFT stack, with the different layers labeled. c, d GI-XRD scan, and average crystallite sizes (with error bar) calculated from the Scherrer’s formula, respectively, of the three different temperatures deposited ZnO films. e, f O1s XPS spectra of the ZnO channel layers deposited at three temperatures as indicated, and plot showing the Zn–O, VO, and −OH atomic percentages (with error bar) as a function of the three different temperatures used12,17,49,50,51.