Improvement of electrical and optoelectronic properties of ZnO thin films by plasma nitridation treatment

Understanding and controlling the effects of trap sites in ZnO semiconductors are crucial for optimizing device performance and enabling various technological applications. To passivate the trap sites, the N atoms are incorporated into polycrystalline ZnO thin films via a plasma nitridation (PN) process using NH3 gas. The results show that the contact resistivity, sheet resistance, and transfer length of the ZnO photodetector are improved after the PN treatment. The photo-to-dark current ratio (PDCR) and responsivity values increase from 42.52 to 103.19 and from 344.36 A/W to 5727.63 A/W, respectively, after the PN treatment. This improvement in photodetector properties is attributed to the introduced N atoms, which effectively reduce the trap sites in the ZnO thin film. This PN treatment technology has the potential to improve device performance in both electronic and optoelectronic applications. •To passivate the trap sites, the N atoms are incorporated into polycrystalline ZnO thin films.•Contact resistivity, sheet resistance, and transfer length of the ZnO photodetector are improved after the PN treatment.•The photo-to-dark current ratio and responsivity values increase from 42.52 to 103.19 after PN treatment.•Introduced N atoms effectively reduce the trap sites in the ZnO thin film.