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: Uncooled bolometer based on La0.7Sr0.3MnO3 thin films: Thermal model, electrical and optical characterizations

Ammar Aryan 1
1 Equipe Electronique - Laboratoire GREYC - UMR6072
GREYC - Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen
Abstract : The aim of this thesis is to evaluate LSMO (La0,7Sr0,3MnO3) thin films deposited on substrate as room temperature radiation detector, by using the variation of its resistance electric near 300 K. An optical measurement setup has been designed and realized to achieve this objective. This setup was to characterize the LSMO samples as bolometrical radiation detector. A detailed thermal model of thin-film-on-substrate structure is proposed. It interprets the variation of the optical responsivity versus the modulation frequency of laser radiation power. The discussion of this model includes presenting the heat diffusion into substrate, and the film-substrate interface thermal resistance. This model has been analyzed and validated using the measurement results of many detection surfaces (meander shape) and substrate materials. The value of film-substrate interface thermal resistance was estimated for different substrates. The bolometer characterization includes the thermal and electrical parameters, like TCR and thermal conductance, needed to qualify its performance. Also, measurement and analysis of optical responsivity and noise for many different pixel surfaces on different substrates is presented. The role of detector geometry (pixel surface, film thickness, and number of strips) and substrate material (SrTiO3, MgO, SrTiO3/Si) on the bolometer performance is studied by using the measurement results and calculation data issued from the proposed model. The measured specific detectivity increases for higher pixel size and lower substrate material thermal conductivity. We estimated 2x107 cm.W-1.Hz1/2 for 200x200 µm² LSMO/STO sample. For LSMO/Si, estimation of 21 µs response time was achieved for 50x50 µm², which is comparable to that of photon detectors.
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Submitted on : Thursday, November 21, 2013 - 5:35:42 PM
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  • HAL Id : tel-00907799, version 1

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Ammar Aryan. : Uncooled bolometer based on La0.7Sr0.3MnO3 thin films: Thermal model, electrical and optical characterizations. Micro and nanotechnologies/Microelectronics. Université de Caen, 2013. English. ⟨tel-00907799⟩

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