Seebeck infrared photodetectors: an ultra wide dynamic range of design possibilities

The theoretical background of Seebeck infrared detectors based on nonlinear free carrier absorption in doped semiconductors has been presented. The 3D-distribution of the electron and lattice temperatures created by the absorption of an optical beam with a cylindrical symmetry in layered structures was developed. Five different operation regimes of the detector are presented, showing that all beams form CW down to picoseconds can be detected. We will discuss how one can control the detectable power and intensity levels and the cross-talk in multi-pixel arrays by means of the doping concentration, geometry of the absorption region and pixellation format, the positioning of a heat sink, and micro-machining techniques. Experimental backing for the model will be given for the pulsed regime and the CW regime. We also demonstrate operation of the detector in the +1 kW power level.