Mid-infrared detection has many applications for military, communication, astronomy and medicine. In the past, mid-infrared detections are mainly based on low-bandgap compound semiconductors. Here we explore mid-infrared detections based on silicon technologies. Utilizing the naturally etched facets of Si to create pyramid structures on Si gives rise to varying dimensions from around 10 nanometers to several micrometers. Then metal is deposited on the Si pyramid structures and is able to have resonant effects for light of various wavelengths. Because the pyramid structures have varying dimension from the tip to the base, a wide range of wavelength could find its corresponding length. As a result, a very broadband response in the infrared spectrum is expected. Light absorption and detection will be experimentally investigated on the Si-based Schottky photodetector with those structures for different metals on Si to detect light of spectral range covering from visible to over 5 um in wavelength.