Simulation of Heat Propagation Processes in Thermoelectric Detection Pixels

Abstract

Processes of heat propagation in thermoelectric detection pixels that occur after absorption of UV single photons with the energy of 3.1–7.1 eV (400–175 nm) were studied by computer simulation method. Designs of detection pixels with a surface of 10 × 10 μm², consisting of layers of the tungsten heat sink (W), the FeSb₂ thermoelectric sensor, the W absorber, and the antireflective layer of SiO₂, arranged in series on the sapphire substrate (Al₂O₃) are considered. Computer simulation was carried out based on the equation of heat propagation from a limited volume using a three-dimensional matrix method for differential equations. The temporal dependence of the temperature change in different areas of detection pixels is calculated for absorber thicknesses of 0.2–0.1 µm and sensor thicknesses 0.1–0.05 µm. The phonon and Johnson noise of the detection pixel SiO₂/W/FeSb₂/W/Al₂O₃ are estimated. It is shown that such detection pixels at the operating temperature of 9 K are capable to detect single photons in the UV region of the spectrum and provide a high signal-to-noise ratio.