Sökning: "hot electron effect"
Visar resultat 1 - 5 av 53 avhandlingar innehållade orden hot electron effect.
1. Graphene Hot-electron Transistors
Sammanfattning : Graphene base transistors (GBTs) have been, recently, proposed to overcome the intrinsic limitations of the graphene field effect transistors (GFETs) and exploit the graphene unique properties in high frequency (HF) applications. These devices utilize single layer graphene as the base material in the vertical hot-electron transistors. LÄS MER
2. NbN and NbTiN Hot Electron Bolometer THz Mixers
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
3. NbN Hot Electron Bolometric Mixers for a Quasi--Optical THz Receiver
Sammanfattning : Experimental work on the development of a quasi-optical heterodyne receiver for the THz frequency range is reported. The mixing device is a superconducting hot electron bolometer (HEB) made from ultrathin, d = 3 - 5 nm, niobium nitride (NbN) films. LÄS MER
4. Studies of Light Emitting Devices Based on Er-doped Si and SiGe Layered Structures
Sammanfattning : Doping with rare earth element erbium (Er) in Si has recently attracted a lot of research interest due to potential applications in Si-based opto-electronics. By using molecular beam epitaxy (MBE), precipitate-free Er-doping in Si has been made together with other co-dopants, e.g., oxygen (0) and fluorine (F), up to a level ∼1020 cm-3. LÄS MER
5. Growth and characterization of SiC and GaN
Sammanfattning : At present, focus of the SiC crystal growth development is on improving the crystalline quality without polytype inclusions, micropipes and the occurrence of extended defects. The purity of the grown material, as well as intentional doping must be well controlled and the processes understood. LÄS MER