Ultra‐Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity

Topological crystalline insulators (TCIs) are predicted to be a promising candidate material for ultra‐broadband photodetectors ranging from ultraviolet (UV) to terahertz (THz) due to its gapless surface state and narrow bulk bandgap. However, the low responsivity of TCIs‐based photodetectors limits their further applications. In this regard, a high‐performance photodetector based on SnTe, a recently developed TCI, working in a broadband wavelength range from deep UV to mid‐IR with high responsivity is reported. By taking advantage of the strong light absorption and small bandgap of SnTe, photodetectors based on the as‐grown SnTe crystalline nanoflakes as well as specific short channel length achieve a high responsivity (71.11 A W^?1 at 254 nm, 49.03 A W^?1 at 635 nm, 10.91 A W^?1 at 1550 nm, and 4.17 A W^?1 at 4650 nm) and an ultra‐broad spectral response (254–4650 nm) simultaneously. Moreover, for the first time, a durable flexible SnTe photodetector fabricated directly on a polyethylene terephthalate film is demonstrated. These results prove the great potential of TCIs as a promising material for integrated and flexible optoelectronic devices.