Väitös teknillisen fysiikan alalta, MSc Libin Wang

Thermal relaxation in nanodevices at sub-kelvin temperatures

Väitöskirjan nimi on "Experiments on thermal relaxation of copper films for nano-calorimetry"

It is well known that when an object with relatively high temperature is brought into contact with a cold thermal reservoir, its energy is released to the reservoir by the thermal flow across the contact interface. For instance, for an externally heated metallic film on a dielectric substrate (thermal reservoir), at room temperature, the energy relaxation of the film is governed by the thermal boundary resistance between the film and the substrate, which is essentially determined by the thermal coupling of phonons (lattice vibrations) on both sides of the interface.

At low temperatures, the thermal relaxation process of metallic films becomes complex due to decoupling of film electrons from its lattice vibrations. In this dissertation, we investigate the thermal relaxation process of evaporated metallic films on a silicon substrate. Experiments are carried out at temperatures closed to the absolute zero and on metallic films of thickness in the nanometer scale. We investigate the thermal relaxation of electrons in metallic films at both steady-state and dynamic conditions. Our experimental results are crucial for the understanding of thermal relaxation in nanodevices and for improving the performance of low temperature detectors utilizing thermal effects.

Vastaväittäjänä toimii professori Evgeni Il'ichev, Leibniz Institut für Photonische Technologien, Saksa.

Kustos on professori Jukka Pekola, Aalto-yliopiston perustieteiden korkeakoulu, teknillisen fysiikan laitos.

Väittelijän yhteystiedot: Libin Wang, Teknillisen fysiikan laitos, [email protected], 0504067497

Elektroninen väitöskirjaVäitöskirja on julkisesti nähtävillä 10 päivää ennen väitöstä Aalto-yliopiston perustieteiden korkeakoulun ilmoitustaululla Konemiehentie 2, Espoo.

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