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The electro-thermal and optical properties of a bolometer based on an La 0.7 Sr 0.3 MnO 3 (LSMO) thin film with a detection area of 100 × 100µm 2 are presented. The LSMO thin film was epitaxially grown on CaTiO 3 /Si and patterned using a two-step etching process of ion-beam etching in argon and of reactive-ion etching in SF 6 , in order to etch LSMO/CaTiO 3 and Si, respectively. The voltage-current (V-I) characteristics of the bolometer were measured in vacuum from 240 to 415 K. From the V-I characteristics and a thermal model of the bolometer, the electrical responsivity was determined and compared to the optical responsivity measured with a laser diode at 635 nm. The noise equivalent power (NEP) as a function of frequency was measured by dividing the spectral noise power density by the optical responsivity. At 300 K and a bias current of 80 µA, the NEP was 2.3×10-11 W•Hz-1/2 in the 20-200 Hz modulation frequency range and the response time was 1.3 ms. The obtained NEP value without any absorbing layer or antennas, combined with the low value of the response time, are a very promising step towards the use of such LSMO-based bolometers for IR or THz detection.

Thermo-resistive sensors are widely used in metrology and instrumentation systems. In the case of radiometers used in measurement of solar radiation, the classical architecture uses the principle of electrical equivalence in which the electrical sensor is kept at a constant temperature. The objective of this study is to evaluate the influence of environmental temperature variation according to the dynamic output voltage of this type of radiometer. In addition, it was evaluated the output dynamic voltage for a constant temperature difference between the sensor and the environment. The sensors used were NTC and PTC, with analog voltage and pulse width outputs.