A Dual-Band Multilayer InSe Self-Powered Photodetector with High Performance Induced by Surface Plasmon Resonance and Asymmetric Schottky Junction.

A dual-band self-powered photodetector (SPPD) with high sensitivity is realized by a facile combination of InSe Schottky diode and Au plasmonic nanoparticle (NP) arrays. Comparing with pristine InSe devices, InSe/Au photodetectors possess an additional capability of photodetection in visible to near-infrared (NIR) region. This intriguing phenomenon is attributed to the wavelength selective enhancement of pristine responsivities by hybridized quadrupole plasmons resonance of Au NPs. It is worth pointing out that the maximum of enhancement ratio in responsivity reaches up to ∼1200% at a wavelength of 685 nm. In addition, owing to a large Schottky barrier difference formed between active layer and two asymmetric electrodes, the responsivities of dual-band InSe/Au photodetector could reach up to 369 and 244 mA/W at the wavelength of 365 and 685 nm under zero bias voltage, respectively. This work would provide an additional opportunity for developing multifunctional photodetectors with high performance based on two-dimensional materials, upgrading their capacity of photodetection in a complex environment.