Photoelectronic device, semiconductor substrate and manufacturing method thereof

The invention provides a photoelectronic device, a semiconductor substrate and a manufacturing method thereof. The semiconductor substrate comprise a silicon substrate and a metal layer positioned on the first surface of the silicon surface, wherein a plurality of grooves are formed in the first surface of the silicon substrate; and the areas among the grooves as well as the bottom surfaces and side walls of the grooves are covered with the metal layer. The grooves and the metal layer on the surfaces of the grooves can serve as U-shaped waveguides, multiple modes of surface plasma polariton excitation exist in the U-shaped waveguides, and the absorption band of the semiconductor substrate can be widened through the multiple modes of surface plasma polariton excitation, so that silicon substrate photoelectronic devices and silicon substrate photoelectric detectors are widely applied.