Fabrication of assembled ZnO/TiO2 heterojunction thin film transistors using solution processing technique

• Assembly of TiO2/ZnO thin film transistors (TFFs) were designed and fabricated.
• Each layer of the transistor was produced by wet processing technique.
• The TiO2 and ZnO films were assembled to be a p–n junction diode.
• p-channel and n-channel TFTs were fabricated by the assemblies.
• The characteristics of the TFTs were evaluated.

Ceramic-based metal–oxide–semiconductor (MOS) field-effect thin film transistors (TFTs), which were assembled by ZnO and TiO2 heterojunction films coated using solution processing technique, were fabricated and characterized. The fabrication of the device began with the preparation of ZnO and TiO2 films by spin coating. The ZnO and TiO2 films that were stacked together and annealed at 450 °C were characterized as a p–n junction diode. Two types of the devices, p-channel and n-channel TFTs, were produced using different assemblies of ZnO and TiO2 films. Results show that the p-channel TFTs (p-TFTs) and n-channel TFTs (n-TFTs) using the assemblies of ZnO and TiO2 films were demonstrated by source-drain current vs. drain voltage (IDS–VDS) measurements. Several electronic properties of the p- and n- TFTs, such as threshold voltage (Vth), on–off ratio, channel mobility, and subthreshold swing (SS), were determined by current–voltage (I–V) data analysis. The ZnO/TiO2-based TFTs can be produced using solution processing technique and an assembly approach.