1.3 Micron Photodetectors Enabled by the SPARK Effect

In this work, we present a graphene-based photodetector specifically engineered to op-erate at a wavelength of 1310 nm. The device leverages the SPARK effect, previously investigated only at 1550 nm. It features a hybrid waveguide structure comprising hy-drogenated amorphous silicon, graphene, and crystalline silicon. Upon optical illumi-nation, defect states release charge carriers into the graphene layer, modulating the thermionic current across the graphene/crystalline silicon Schottky junction. The photo-detector demonstrates a peak responsivity of 0.3 A/W at 1310 nm, corresponding to a noise-equivalent power of 0.4 pW/Hz¹/². The experimental results provide deeper insights into the SPARK effect by enabling the determination of the efficiency × lifetime product of carriers at 1310 nm and its comparison with values previously reported at 1550 nm. The wavelength dependence of this product is analyzed and discussed. Additionally, the response times of the device are measured and evaluated. The silicon-based fabrication approach employed is versatile and does not rely on sub-micron lithography techniques. Notably, reducing the incident optical power en-hances the responsivity, making this photodetector highly suitable for power monitoring applications in integrated photonic circuits.