(color online) Normalized photoconductivity of NWs photo-detector is plotted versus irradiation proton (1 MeV) fluence, the dashed line is according to the fitting formula and * is the measured data which is extracted from light current I–V curve at −0.5 V. (Goodness of fit: SSE ∼ 0.001706, R-square ∼ 0.9977).