Fast thermoelectric photodetector for UV radiation

Week radiation and single photon detectors have many applications in different areas of modern science and technology. In this work, we study the multi-layer thermoelectric photodetector's detection pixel consisting of a heat sink (Bi2223), thermoelectric sensor (CeB₆), absorber (Bi2223), and antireflection layer (SiO₂) for UV single photon detection. We examine heat transfer after 3.1 eV and 7.1 eV energy photon absorption in the SiO₂/Bi2223/CeB₆/Bi2223/Al₂O₃ detection pixel. The operating temperature for this structure is 9 K. Computer simulation was carried out based on the equation of heat distribution from a limited volume using the three-dimensional matrix method for differential equations. We study the detector's signal, count rate, and noise dependence from detection pixel geometry. Calculations show that after absorption of photons with an energy of 7.1 eV the generated signal maximum will be about 127 nV and achieved up to 10 ps after photon absorption. The full width at half maximum of the obtained signal is from 34 – 228 ps, depending on the detection pixel layer thicknesses. Such a signal can be registered without preliminary amplification. It is shown that this detection pixel provides a gigahertz count rate. Using Bi2223 high-temperature superconductors as an absorber and heat sink allowed less Johnson noise.