The performance of a VO 2 thin-film microbolometer has been investigated. The device is operated within 35°C Ͻ T Ͻ 60°C, in the hysteretic metal-insulator transition region. An algebraic hysteresis model has been used to model the resistance-temperature characteristic of the sensor. It accurately describes the resistance versus temperature characteristics of the material. Employing this model, and in conjunction with established bolometer theory, the responsivity of a VO 2 film is calculated and compared with experimental data. Superior performance of the device is achievable under conditions of single pulse incident radiation where the operating point remains on the major hysteresis loop. This results in a pronounced responsivity peak within the center of the metal-insulator transition. Continuous periodic excitation, in contrast, leads to a steadily decreasing and much lower sensitivity at higher temperature, due to the formation of minor hysteresis loops and the loop accommodation process.

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The review describes the noise properties of the high temperature superconducting (HTS) bolometers developed for the applications in the optical electronic devices of infrared and submillimeter wave-lengths. The principle of high-Tc transition edge bolometer operation and bolometer noise theory are considered, taking into account the peculiarities of constant bias current and constant bias voltage modes. The published results of bolometer noise modeling are discussed. Various sources of the excess 1/f-noise in HTS films as temperature sensitive element for bolometer are reviewed, including the experimental data and modern noise models. Comparative analysis of noise characteristics of the most developed HTS bolometers for application (antenna-coupled microbolometers and bolometers based on silicon micromachining technology) is reported.

Local measurements of structural characteristics such as intrinsic microstrain along the c axis of the lattice ε=δc/c and its mean square fluctuation 〈ε〉, oxygen deficiency x, cation composition, etc. were performed on epitaxial YBa2Cu3O7 films grown on various substrates (MgO, BaSrTiO3/MgO, SrTiO3, LaAlO3, ZrO2/Si, Al2O3). A number of film microstrips were fabricated and the normalized flicker noise intensity (Hooge parameter α) and the resistivity ρ at 300 K were measured at each characterized point. A theoretical model was developed that explains the observed first growth of α with 〈ε〉 and the well-known high level of the normal-phase flicker noise in various high temperature superconducting compounds. Comparison of the experimental and simulated dependence of α on 〈ε〉, frequency, and temperature permits one to determine numerically the theoretical parameters of the double-well potential with minima located at the chain (O1) and empty (O5) oxygen lattice positions of the CuO plane.

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Superconducting transition edge bolometers on micromachined silicon membranes have been fabricated. The optical response is 580 V/W at a time constant of 0.4 ms. The detectivity D* is 3.8×109 (cm Hz1/2 W−1) at a temperature of 84.5 K and within the frequency regime 100<f<300 Hz. This is one of the fastest composite type bolometers ever reported. Upon thermal optimization, this type of detector should be competitive with state-of-the-art quantum detectors.

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