Effects of vacuum annealing on the optical and electrical properties of p-type copper-oxide thin-film transistors

Abstract

We have investigated the effects of vacuum annealing on the optical and electrical properties of the p-type copper-oxide thin-film transistors (TFTs). The vacuum annealing of the copper-oxide thin-film was performed using the RF magnetron sputter at various temperatures. From the x-ray diffraction and UV-vis spectroscopy, it is demonstrated that the high-temperature vacuum annealing reduces the copper-oxide phase from CuO to Cu2O, and increases the optical transmittance in the visible part of the spectrum. The fabricated copper-oxide TFT does not exhibit the switching behavior under low-temperature vacuum annealing conditions. However, as the annealing temperature increases, the drain current begins to be modulated by a gate voltage, and the TFT exhibits a high current on-off ratio over 10(4) as the vacuum annealing temperature increases over 450 degrees C. These results show that the vacuum annealing process can be an effective method of simultaneously improving the optical and electrical performances in p-type copper-oxide TFTs.