Sökning: "doubly clamped"

Hittade 5 avhandlingar innehållade orden doubly clamped.

1. 1. Integration of graphene into MEMS and NEMS for sensing applications

   Författare :Xuge Fan; Frank Niklaus; Peter Steeneken; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Micro-electromechanical systems MEMS ; Nano-electromechanical systems NEMS ; heterogeneous 3D integration; Graphene; single-layer graphene; double-layer graphene; bilayer graphene; chemical vapor deposition CVD ; suspended graphene beams; suspended graphene membranes; doubly clamped; fully clamped; silicon on insulator SOI ; vapor hydrofluoric acid VHF ; Young’s modulus; built-in stress; built-in tension; piezoresistivity; gauge factor; accelerometer; resonators; electromechanical sensing; advanced transducers; humidity; gas sensing; sensitivity; CO2 sensing; graphene grain boundary; line defects; optical microscopy; wire bonding; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis presents a novel approach to integrate chemical vapor deposition (CVD) graphene into silicon micro- and nanoelectromechanical systems (MEMS/NEMS) to fabricate different graphene based MEMS/NEMS structures and explore mechanical properties of graphene as well as their applications such as acceleration sensing, humidity sensing and CO2 sensing. The thesis also presents a novel method of characterization of CVD graphene grain boundary based defects. LÄS MER

3. 2. Self Oscillations and Cooling of Carbon Based NEMS Devices

   Författare :Anders Nordenfelt; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nano electro-mechanics; carbon nanotubes;

   Sammanfattning : We investigate the electromechanical properties of a number of system geometries featuring a doubly clamped Carbon Nanotube or Graphene sheet with a deflection sensitive resistance and an electronic feedback in the form of a Lorentz force or an electrostatic attraction. The nanotube is subjected to a constant current- or voltage bias and it is shown that when the electro-mechanical coupling exceeds a certain critical value the system becomes unstable to self-excitations of the mechanical vibrations accompanied by oscillations in the voltage drop and current through the nanotube. LÄS MER

4. 3. Modeling Carbon Nanotube Field Effect Transistors with Fixed and Suspended Nanotube Gates

   Författare :Yury Tarakanov; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Carbon nanotubes (CNT) exhibit a range of properties that make them well suited for nanoelectronic and nanoelectromechanical devices. One-dimensional field effect transistors based on single-walled CNTs have demonstrated excellent electrical characteristics and are competitive with silicon-based solutions, and oscillators based on suspended CNTs have been shown to work at gigahertz frequencies with Q-factors exceeding 10$^3$. LÄS MER

5. 4. Electromechanical Instability in Suspended Nanowire-Based NEMS

   Författare :Fabio Santandrea; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NEMS; Shuttle instability; Coulomb blockade; Carbon Nanotubes; Electronic Transport; Nonlinear Dynamics;

   Sammanfattning : "Nanoelectromechanical systems'' (NEMS) are a class of nanometer-sized mechanical structures coupled to electronic device of comparable dimensions. Their peculiar features make them interesting both from the technological and fundamental research viewpoints. LÄS MER

7. 5. Electronic Control of Flexural Nanowire Vibrations

   Författare :Fabio Santandrea; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; Carbon nanotubes; Coulomb blockade; Shuttle instability; Ground-state cooling;

   Sammanfattning : “Nanoelectromechanical systems” (NEMS) are nanometer-sized mechanical structures coupled to electronic devices of comparable size. The coupling between mechanical and electronic degrees of freedom, combined with their mesoscopic size, provide these systemswith some unique properties that make them interesting from both the fundamental and technological point of view. LÄS MER