Ultrathin 2D ternary Bi2Te2Se flakes for fast-response photodetectors with gate-tunable responsivity

Two-dimensional (2D) ternary materials have sprung up in a broad variety of optoelectronic applications due to their robust degree freedom design the physical properties through adjusting stoichiometric ratio. However, controlled growth high-quality 2D with good chemical stoichiometry remains challenging, which severely impedes further development and future device applications. Herein, we synthesize Bi2Te2Se (BTS) flakes thickness down 4 nm lateral dimension about 60 µm by an atmospheric-pressure solid source thermal evaporation method on mica substrate. The phonon vibration electrical transportation BTS are respectively investigated temperature-dependent Raman spectrum conductivity measurements. Furthermore, photodetector based exhibits excellent performance high light on/off ratio 1300 (365 nm), wide spectral response range from 365 980 nm, ultra-fast speed 2 µs. In addition, its photoelectric can be modulated gate voltage, offering improved infrared responsivity 2.74 A W−1 2266 under nm. This work introduces effective approach obtain demonstrates prospects optoelectroni cs.