Scalable fabrication of Bi2O2Se polycrystalline thin film for near-infrared optoelectronic devices applications*

We present a controlled, stepwise formation of layered semiconductor Bi 2 O 2 Se thin films prepared via the vapour process by annealing topological insulator Bi 2 Se 3 thin films in low oxygen atmosphere for different reactions. Photodetectors based on Bi 2 O 2 Se thin film show a responsivity of 1.7 × 10 4 A/W at a wavelength of 980 nm. Field-effect transistors based on Bi 2 O 2 Se thin film exhibit n-type behavior and present a high electron mobility of 17 cm 2 /V⋅s. In addition, the electrical properties of the devices after 4 months keeping in the air shows little change, implying outstanding air-stability of our Bi 2 O 2 Se thin films. From the obtained results, it is evident that low oxygen annealing is a surprisingly effective method to fabricate Bi 2 O 2 Se thin films for integrated optoelectronic applications.