Sökning: "hot electrons"
Visar resultat 1 - 5 av 33 avhandlingar innehållade orden hot electrons.
Sammanfattning : Time-resolved photoemission electron microscopy (TR-PEEM) belongs to a class of experimental techniquescombining the spatial resolution of electron-based microscopy with the time resolution of ultrafast opticalspectroscopy. This combination provides insight into fundamental processes on the nanometer spatial andfemto/picosecond time scale, such as charge carrier transport in semiconductors or collective excitations ofconduction band electrons at metal surfaces. LÄS MER
Sammanfattning : The thesis reports the development of Hot Electron Bolometer (HEB) mixers for radio astronomy heterodyne receivers in THz frequency range. Part of this work is the fabrication of HEB devices, which are based on NbN or NbTiN superconducting thin films (≤5 nm). They are integrated with wideband spiral or double-slot planar antennas. LÄS MER
Sammanfattning : The relatively recent discovery that plasmonic nanoparticles generate energetic electron-hole pairs known as hot carriers has been the source of interest from many scientific groups. The capability to extract these short-lived hot carriers from metal nanoparticles (NPs) might potentially lead to applications in solar cells, photodetection, and photocatalysis. LÄS MER
Sammanfattning : A technology of encapsulation of graphene in Parylene was introducedas an alternative to encapsulating graphene in hBN. Edge contacts to theencapsulated graphene in this case showed resistivity down to 14 Ohm um,which is the lowest reported value so far. LÄS MER
Sammanfattning : In the Joint European Torus (JET) tokamak, monster sawtooth stabilisation by ICRH-accelerated hot ions is lost if plasma density falls below a certain density threshold, or if energetic-ion driven Alfvén eigenmodes inside q = 1 occur. In the first case, a transition away from long periodmonster sawteeth to a regime with shorter period, chaotic sawteeth (grassy sawteeth) takes place, while in the second case the monster sawtooth crash happens, degrading plasma confinement. LÄS MER