Fully Solution-Processed Sodium Doped ZnO Thin-Film Transistors via a Low- Temperature Aqueous Route

In this study, we develop a simple and eco-friendly aqueous route for the fabrication of sodium (Na) doped ZnO/AlO
_x
thin-film transistors (TFTs). To prepare Na doped ZnO and AlO
_x
thin films, ammonia water and deionized water were used as the precursor solvents. The AlO
_x
thin film annealed at 300°C showed an areal-capacitance of 129 nf/cm
²
at 1 kHz. On the basis of its implementation as the gate oxide, fully solution-processed Na doped ZnO TFTs were fabricated and the electrical characteristics were systematically studied. The fully solution processed Na doped ZnO/AlO
_x
TFTs exhibited a high field effect mobility of 21 cm
²
V
^-1
s
^-1
, a subthreshold swing of 0.58 V/decade, a threshold voltage of 0.8 V, and an on/off current ratio of 2×10
⁴
.