Vis–IR Wide-Spectrum Photodetector at Room Temperature Based on p–n Junction-Type GaAs_1–xSb_x/InAs Core–Shell Nanowire

Infrared (IR) detection at room temperature is very important in many fields. Nanoscale wide-spectrum photodetectors covering IR range are still rare, although they are desired in many applications, such as in integrated optoelectronic devices. Here, we report a new kind of photodetector based on p–n heterojunction-type GaAs1–xSbx/InAs core–shell nanowires. The photodetectors demonstrate high response to the lights ranging from visible light (488 nm) to short-wavelength IR (1800 nm) at room temperature under a very low bias voltage of 0.3 V. The high performance of the devices includes an ultralow dark current (32 pA at room temperature), a high response speed (0.45 ms) to 633 nm light, high responsivity to 1310 nm telecommunication light (0.12 A/W), high response even to 1800 nm light (on/off ratio of 2.5), etc. Besides, the devices also show excellent rectifying I–V characteristics (the current rectification ratio being ∼178 in a voltage range of ±0.3 V). These results suggest that the GaAs1–xSbx/InAs core–shell nanowire devices are promising for applications in nanoelectronic devices, optoelectronic devices, and integrated optoelectronic devices.