Ultralow-voltage and high gain photoconductor based on ZnS:Ga nanoribbons for the detection of low-intensity ultraviolet light

A low-intensity ultraviolet photodetector (PD), with a gain as high as similar to 2.4 X 106, has been successfully constructed based on gallium (Ga) doped zinc sulfide (ZnS) nanoribbons (NRs). The device exhibits excellent photoconductive properties upon a bias voltage as low as similar to 0.01 V in terms of high sensitivity to UV light with an intensity of 1 mu W cm(-2) (corresponding to an incident power of 10 similar to 14 W), relatively fast response times of similar to 3.2 ms, and an extremely high detectivity of similar to 1.3 similar to 10(19) cm Hz(1/2) W-1. The high gain and fast response time are attributed to the excellent ohmic contact obtained by using a high quality ITO electrode and having a carrier mobility as high as 130 cm(2) V-1 s(-1), which was confirmed from the back-gate field effect transistors. These results show that the single-crystalline n-type ZnS: Ga NRs will have potential applications in future high-performance low-intensity ultraviolet photodetectors.