Fig. 1. （a）The schematic diagram of the synthesis process，（b）the schematic diagram of the device，（c）the optical image of the device.

Fig. 2. （a）The SEM image of a single Se microrod，（b）the XRD pattern of Se microrods，（c）the absorption spectrum of Se microrods. The insert is the calculated bandgap image，（d）the Raman spectrum of the Se microrod.

Fig. 3. （a）The I-V curves of the device in dark and under 450 nm illumination with different light intensities，（b）the I-T curve of the devices under 450 nm illumination at 3 V bias voltage，（c）the response time of the device under 450 nm illumination at 3 V bias voltage，（d）The responsivity and detectivity of the device under 450 nm illumination with different light intensities at ±3 V bias voltage。

Fig. 4. （a）The photocurrent distribution of the device under light illumination with different wavelengths，（b）the responsivity and detectivity of the device under light illumination with different wavelengths at ±3 V bias voltage，（c）the I-T curve of the device under 450 nm illumination without bias，（d）the response time of the device under 450 nm illumination without bias.