Ultrasensitive broadband photodetectors based on two-dimensional Bi₂O₂Te films

Two-dimensional (2D) materials exhibit many unique optical and electronic properties that are highly desirable for application in optoelectronics. Here, we report the study of a photodetector based on 2D Bi₂O₂Te grown on ann-Si substrate. The 2D Bi₂O₂Te material was transformed from a sputtered Bi₂Te₃ultrathin film after rapid annealing at 400 °C for 10 min under an air atmosphere. The photodetector was capable of detecting a broad wavelength ranging from 210 nm to 2.4 μm with an excellent responsivity of up to 3 × 10⁵and 2 × 10⁴AW⁻¹and a detectivity of 4 × 10¹⁵and 2 × 10¹⁴Jones for deep ultraviolet (UV) and short-wave infrared (SWIR) under weak light illumination, respectively. The effectiveness of 2D materials in weak light detection was investigated by the analysis of the photocurrent density contribution. Importantly, the facile growth process at low annealing temperatures would allow the direct large-scale integration of 2D Bi₂O₂Te materials with the complementary metal-oxide-semiconductor (CMOS) technology.