Interfacial defect engineering of AZO electron transport layers via UV ozone treatment for polymer photodetectors

초록

Controlling oxygen vacancies in metal oxide thin films is critical for enhancing charge transport and interfacial stability in polymer photodetectors (PPDs). Ultraviolet (UV) ozone treatment is an effective approach for modulating oxygen vacancies. We investigated the effects of UV ozone treatment on aluminum-doped zinc oxide (AZO) and the performance of PPDs incorporating these films. At -2 V, treatment times of 10 and 20 min reduced the dark current density from 2.46 & times; 10-4 A/cm2 (untreated) to 4.24 & times; 10-5 and 6.05 & times; 10-5 A/cm2, corresponding to 5.8-fold and 4.0-fold reductions, respectively, and increased the specific detectivity (Dshot*) at 700 nm from 4.68 & times; 1010 to 1.12 & times; 1011 Jones. These treatment times also increased the fill factor to 61.5% and 60.5%, respectively, compared to 56.9% for untreated devices. Optical and electrical analyses revealed that increasing treatment time reduced the optical bandgap, increased interfacial barrier resistance, reduced bulk capacitance, and improved surface morphology. X-ray photoelectron spectroscopy confirmed decreased oxygen vacancies and enhanced metal-oxygen bonding. However, treatment beyond 30 min induced surface degradation and excessive resistivity, limiting device performance. These results demonstrate that UV ozone treatment offers a simple yet effective route to engineering metal oxide interfaces and achieving high-performance PPDs.

키워드