A nanoscale Inverse-Extraordianry Optoconductance (I-EOC) efficient room temperature photodetector

We present here a new nanoscale efficient photon sensor based on a new form of extraordinary optoconductance phenomenon, (EOC), in nanoscopic metal-semiconductor hybrid structures (MSH) at room temperature. Our macroscopic devices (dimension $>$ 500 nm) exhibit a normal EOC in which the effective resistance decreases with increased illumination intensity, whereas nanoscopic structures (dimension $<$ 500 nm) of the same geometric design exhibit an inverse and much larger response in which the effective resistance increases with illumination intensity. This inverse EOC (I-EOC) effect is driven by the cross-over from ballistic to diffusive transport of the photo-induced carriers. We observe at room temperature a maximum I-EOC of $9460\%$ for a 250 nm device under 633 nm illumination corresponding to a specific detectivity of $D^* = 3.2\times 10^{11}$ cmHz$^{1/2}$/W with a dynamic response of 40 dB making this sensor technologically competitive for a wide range of nanophotonic applications.