Photoelectric properties of exfoliated few-layer Bi2O2Se nanoflakes

Bi₂O₂Se was discovered as a promising two-dimensional (2D) semiconductor with high electron mobility, ultrafast photoresponse and excellent environmental stability. However, as so far, only chemical vapor deposition (CVD) Bi₂O₂Se nanofilms have been investigated and reported. Here, we firstly systematically studied the electrical and photoelectric properties of exfoliated few-layer Bi₂O₂Se nanoflakes. Results indicate that exfoliated Bi₂O₂Se based field effect transistor (FET) exhibited high mobility (~ 460 cm²V^-1s^-1) and high conductance (~ 4.9 mS). In addition, Exfoliated few-layer Bi2O2Se based photodetector demonstrates an ultra-sensitive photoresponse with good reproducibility at room-temperature for visible wavelengths, including a high photoresponsivity (~125 mA/W), a quick response time (< 40 ms) and a high external quantum efficiency (~ 30 %). These results offer the opportunities for developing the next generation of ultrasensitive high performance room-temperature photodetectors based on exfoliated few-layer Bi₂O₂Se nanoflakes.