(color online) Metal–insulator–semiconductor structured self-powered photodetector and its performance optimization under strains. (a) Schematic diagram of detector. (b) Side-view morphology of the ZnO nanorods array. (c) Morphology of the insulator layer. (d) Photoresponsivity of detector. (e) Photocurrent response under different compressive strains. (f) Resistance variation under different compressive strains. Inset is the equivalent circuit.