Abstract: A substrate with a low-reflection surface film and structure is provided. A germanium-tin (GeSn) layer or a silicon-germanium-tin (SiGeSn) layer is arranged on an upper surface of a semiconductor substrate as a low-reflection film. A thickness of the low-reflection film is in a range of 10 nm to 10 ?m, and an upper surface of the low-reflection film is a rough surface. An electronic element formed on the substrate with a low-reflection surface film and structure has a higher absorption for a light source of the same intensity, the response of a photodetector can be improved, and the photoluminescence (PL) intensity can be enhanced.