Metasurfaces can be used to enhance the absorption in metallic and dielectric thin films. Taking advantage of this property, we experimentally demonstrate the use of a commercially available thermoelectric device as a thermoelectric photodetector by integrating it with a metallic metasurface array operating as an absorption enhancer for both the visible and the short-wave infrared. Electrical measurement shows that the responsivity of the nanostructured region is an order of magnitude higher than the flat film region. The absorption spectrum and correspondingly the spectral response of the device can be tailored by optimizing the metasurface dimensions. As such, the device can be used as a multiband photodetector for diverse applications.