Effects of Ni Doping Composition on the Physical and Electrical Properties of Cu_1-xNi_xO Thin-Film Transistors

Compared to n-type oxide thin-film transistors (TFTs) with excellent performance, the physical properties of p-type oxide films and their TFTs performance still need to be explored. Here, the Ni-doped CuO (Cu1-xNixO) films were prepared by the solution-processed method. Compared to pure CuO film, the doping of Ni can promote the crystallization of Cu1-xNixO films. By analysis of the spectroscopic ellipsometry (SE), the optical bandgap of Cu1-xNixO films can be modulated from 2.16 to 2.35 eV with increasing the Ni composition. Moreover, the electrical curves of Cu1-xNixO TFTs demonstrate a typical p-type semiconducting behavior. The TFT with a Ni composition of 0.5% shows the optimal performance with a carrier mobility of 0.01 cm2V-1s-1, a threshold voltage of 3.72 V, and a subthreshold swing of 5.35 V/dec. This work provides an efficient approach to modulate the device performance of p-type CuO TFTs.