ZnO nanostructure thin film transistors on plastic substrate prepared by solution method and pH sensing properties

Abstract

<p>We fabricated a ZnO nanostructures based TFT on plastic substrate by solution method under low temperature. ZnO nanostructures were prepared by zinc nitrate hexahydrate, and hexamethylenetetramine. The device shows hard saturation characteristics and exhibits a high off-resistance. The output characteristics devices also shows current saturation and pinch off behavior, in which the high of current saturation obtained 266 mA at <em>V<sub>GS</sub></em> = 40 V and <em>V<sub>DS</sub></em> = 42.5 V. The pH response on the electrical properties was also studied. It was found that the threshold voltage shifted from 10.21 V to 13 V as pH solution gradually increased. The <em>I<sub>on</sub>/I<sub>off</sub></em> for as grown TFTs and TFTs with pH response of 10.21 shifted from 1.86 x 10<sup>5</sup> to 7.03 x 10<sup>6</sup> at <em>V<sub>DS</sub> </em>= 20 V. The obtained sensitivity of devices was 1.05 V/pH.</p>