High-Performance Flexible ZnO Thin-Film Transistors by Atomic Layer Deposition

Flexible zinc oxide thin film transistors (ZnO TFTs) with a mobility of 13 cm(2)/V.s and an I-on/I-off ratio of 1.5 x 10(8) have been fabricated on polyimide substrate, where the ZnO channel is deposited by atomic layer deposition (ALD) at 140 degrees C. High bending stability has been achieved due to excellent interface quality between alumina (Al2O3) dielectric and ZnO channel with a sharp interface topography. The flexible-ZnO device exhibits-excellent electrical characteristics even after being bent for 200 000 cycles with a tensile strain of 0.63%. Electrical-measurement under a high tensile strain of 2.08% has also been carried out. Moreover, the electrical performance dependence of flexible ZnO TFTs with a tensile strain of 0.78% on temperature from 20 degrees C to 140 degrees C has been investigated for the first time.