Nanomaterials (Jun 2020)

Channel Defect Profiling and Passivation for ZnO Thin-Film Transistors

  • Soo Cheol Kang,
  • So Young Kim,
  • Sang Kyung Lee,
  • Kiyung Kim,
  • Billal Allouche,
  • Hyeon Jun Hwang,
  • Byoung Hun Lee

DOI
https://doi.org/10.3390/nano10061186
Journal volume & issue
Vol. 10, no. 6
p. 1186

Abstract

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The electrical characteristics of Zinc oxide (ZnO) thin-film transistors are analyzed to apprehend the effects of oxygen vacancies after vacuum treatment. The energy level of the oxygen vacancies was found to be located near the conduction band of ZnO, which contributed to the increase in drain current (ID) via trap-assisted tunneling when the gate voltage (VG) is lower than the specific voltage associated with the trap level. The oxygen vacancies were successfully passivated after the annealing of ZnO in oxygen ambient. We determined that the trap-induced Schottky barrier lowering reduced a drain barrier when the drain was subjected to negative bias stress. Consequentially, the field effect mobility increased from 8.5 m2 V−1·s−1 to 8.9 m2 V−1·s−1 and on-current increased by ~13%.

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