Bicontinuous oxide heterostructures based on mixed zinc oxide/tin dioxide film for high photoconductivity

Here, a bicontinuous oxide heterostructure film based on zinc oxide (ZnO) and tin dioxide (SnO2) is proposed for effiecient photodetection applications. XRF reveals that mixed ZnO/SnO2 film contains about equal element percentages of Zn (43.8 %) and Sn (41.7 %). XRD and SEM confirm the superior crystallinity of the heterostructure of the mixed ZnO/SnO2 film. The bandgap energies of ZnO and SnO2 films are calculated to be 3.17 eV and 3.31 eV. On the other hand, the mixed ZnO/SnO2 heterostructure film has a lower bandgap energy of 2.92 eV, which can be attributed to the fact that the heterostructure can generate the electron from the valence band of SnO2, and the holes could assemble at the conduction band of ZnO. The photoresponsivity of mixed ZnO/SnO2 film is higher than that of pure ZnO and pure SnO2 films. Additionally, the current of mixed ZnO/SnO2 film as a function of time exhibits good consistency and repeatability with rectangular profiles. It can be concluded that mixed ZnO/SnO2 film is considered a potential candidate for photodetector devices.