Preparation of Ti-Doped ZnO/Bi2O3 Nanofilm Heterojunction and Analysis of Microstructure and Photoelectric Properties

Ti-doped ZnO (TZO) and Bi2O3 thin films were designed and deposited by magnetron sputtering successively on ITO glass substrate to form a Ti-doped ZnO/Bi2O3 (TZO/Bi2O3) heterojunction. Microstructure and photoelectric properties of TZO, Bi2O3, and TZO/Bi2O3 films were tested and characterized. The results showed that TZO film with a hexagonal wurtzite structure was preferentially grown along the crystal plane (002), had a good crystallization state, and was an N-type semiconductor film with high transmittance (90%) and low resistivity (4.68 × 10−3 Ω·cm). However, the Bi2O3 film sputtered in an oxygen-containing atmosphere and was a polycrystalline film that was preferentially grown along the crystal plane (111). It had a lower crystallization quality than TZO film and was a P-type semiconductor film with low transmittance (68%) and high resistance (1.71 × 102 Ω·cm). The I–V curve of TZO/Bi2O3 composite films showed that it had an obvious heterojunction rectification effect, which indicates that the PN heterojunction successfully formed in TZO/Bi2O3 films.