Fabrication of silicon carbide-on-silcon based devices for effective near-field thermal radiation transfer

Elçioğlu, Elif Begüm
Near-field radiative transfer (NFRT) has attracted attention due to the potential of obtaining improved amount of heat transfer between media separated by distances comparable to or smaller than the dominant wavelength of emission. Such potential has been demonstrated in vacuum environments to form the basis of mainly near-field thermophotovoltaic systems and further, conversion into electricity with high system efficiency. In this thesis, an analytical analysis is performed to gain insight on nearfield radiative transfer of p- and n-type Si, GaAs, InSb, InP wafers, along with SiC. Results show that the wafer type, doping level, and crystal structure are effective parameters on such systems. The spectral NFRT flux between SiC and n-type InSb pair exceeded the blackbody limit by more than 3 orders of magnitude. Along with the analytical studies, another objective of this thesis is to conceptualize and construct a device consisting of SiC-on-Si media, bonded through patterned SiO2 walls, encapsulating vacuum towards a nanoscale gap. SiC, supporting surface phonon polaritons which is studied in detail in relation to its crystallization behavior through thermal annealing. Here it is aimed to investigate its phononic behavior both in the amorphous and crystalline states. To the best of the author’s knowledge, a materials crystal state dependence of near-field radiative transfer is discovered for the first time, in this dissertation. Achievements and challenges faced during the fabrication of a NFRT device are presented in detail. The proposed device is designed and fabricated to operate under ambient conditions, and explore a wider application framework.


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Radiative heat transfer in nanostructures with sub-wavelength dimensions can exceed that predicted by Planck's blackbody distribution. This increased effect is due to the tunneling of infrared radiation between nanogaps, and can allow the eventual development of nano-thermo-photo-voltaic (Nano-TPV) cells for energy generation from low temperature heat sources. Although near field radiation effects have been discussed for many years, experimental verification of these effects is very limited so far. In this ...
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Near-field radiative transfer (NFRT) refers to the energy transfer mechanism which takes place between media separated by distances comparable to or much smaller than the dominant wavelength of emission. NFRT is due to the contribution of evanescent waves and coherent nature of the energy transfer within nano-gaps, and can exceed Planck's blackbody limit. As researchers further investigate this phenomenon and start fabrication of custom-made platforms, advances in utilization of NFRT in energy harvesting ap...
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Citation Formats
E. B. Elçioğlu, “Fabrication of silicon carbide-on-silcon based devices for effective near-field thermal radiation transfer,” Ph.D. - Doctoral Program, Middle East Technical University, 2018.