Flexible Near-Infrared InGaSb Nanowire Array Detectors with Ultrafast Photoconductive Response Below 20 µs

High-performance flexible room-temperature near-infrared (NIR) photodetectors are one of the important components for image sensing, data communication, environmental monitoring, and bioimaging applications. However, there is still a lack of suitable device channel materials to provide high sensitivity as well as good mechanical flexibility for photodetection, particularly operating at the optical communication wavelength of 1550 nm. In this work, highly crystalline In_0.28Ga_0.72Sb nanowires (NWs) are successfully grown by the two-step chemical vapor deposition method and assembled into high-density regular NW parallel arrays on polyimide substrates. When they are constructed into photodetectors without using any p–n junctions, they exhibit the excellent responsivity up to 1520 A W⁻¹ and ultra-fast response speed below 20 µs toward 1550 nm irradiation at room temperature, which constitutes a record high performance among all flexible NIR photodetectors reported in recent literature. Notably, these flexible NW parallel-array photodetectors also display a superior mechanical flexibility and operation durability. They not only provide a stable photoresponse under illumination on–off cycles up to 1000 s, but also maintain the steady photocurrent without any significant degradation after 700 bending cycles. All these results evidently indicate the promising potential of these crystalline In_0.28Ga_0.72Sb NW parallel arrays for next-generation flexible optoelectronic devices.