A figure of merit (FOM) Z = Up/τr, where Up is the peakvoltage, and τr is the rise time of the laser-inducedthermoelectric voltage (LITV) signal, is defined for photodetector basedon the LITV and the influence of the parameters on FOM is analysed basedon the time dependence of LITVs in La1−xCaxMnO3 (LCMO)and YBa2Cu3O7−σ (YBCO) thin films grown on vicinal-cutsubstrates. We find that the FOM increases as the photon penetrationdepth decreases, and linearly increases with the thermal diffusionconstant D. To achieve the highest FOM, the film thickness d has to becontrolled to an optimum value. We also find that the FOM is directlyproportional to the laser absorption coefficient α0, thelaser energy density per pulse E, the illuminated length of film l,sin(2α) [αis the vicinal-cut angle], the Seebeckcoefficient anisotropy (Sab−Sc), and is inverselyproportional to the mass density ρ and the specific heat c0.
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