The thermoelectric detector consists of an absorber structure supported by two electrically connected beams made of thermoelectric materials such as polysilicon, polysilicon/germanium, bismuth-telluride, skutterrides, superlattice structures, nano-composites and other materials. One end of the thermoelectric beam connects to the absorber structure; the other end connects to the substrate. Infrared radiation incident on the absorber heats up the absorber, resulting in a temperature gradient along the length of the thermoelectric legs, and generating an electrical voltage. The detector arrays are fabricated using micromachining process. The absorber structure is formed over a sacrificial material that is removed at the end of the processing, leaving the detector suspended and thermally isolated. The sacrificial processing method enables the production of small pixel thermoelectric detectors in large two-dimensional arrays with high sensitivity.