Features of Heat Propagation in a Multilayer Thermoelectric Sensor when Absorbing Single Photons with Energy of 0.8 eV at Various Depths of a Composite Absorber

Computer simulation was used to study the characteristics of heat propagation processes in a four-layer SiO2 + LaB6/Mo/ La0.99Ce0.01B6/Mo sensor mounted on an Al2O3 substrate. The sensor has a dielectric absorber made of a composite material consisting of SiO2 and 30 vol % LaB6 nanoparticles, a Mo reflector/electrical contact, a La0.99Ce0.01B6 thermoelectric layer, and a Mo heat sink/electrical contact. Heat propagation from the thermalization zone of single photons with an energy of 0.8 eV, localized in the absorber at a depth of 15–80 nm, is examined. Computer modeling was performed using a three-dimensional matrix method based on the equation for heat propagation from a confined volume. The temporal dependences of temperature at various distances from the center of the sensor layer surfaces and the average temperature of the layers surface are studied. The obtained results allow us to calculate the signal-to-noise ratio of the sensor, which determines the efficiency of detecting an absorbed photon. It is shown that this efficiency changes only slightly with changing the depth of the thermalization zone.