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Open Access Publications from the University of California

Scholarly Works (2 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2017)

Transmission electron microscopy (TEM) is one of the few techniques capable of imaging nanoscale systems in situ. We developed in situ TEM device architectures that allow for TEM imaging without sacrificing device function in order to study device novel nanoelectronic devices. Our slant-vertical device architecture enabled us to observe resistive memory switching cycles for the first time.

While TEM is capable of unparalleled spatial resolution, conventional TEM contrast is determined only by the physical structure of samples; TEM contrast is blind to the electronic structure of devices. We developed novel scanning TEM electron beam-induced current (STEM EBIC) imaging modes and, for the first time, demonstrated its use for qualitative thermal and connectivity mapping as well as quantitative potential and thickness measurements. We demonstrated these STEM EBIC modes with sub-nanometer spatial resolution.

We used conventional TEM imaging along with STEM EBIC to observe functioning conductive bridge (CBRAM) and valence change (VCM) resistive memory elements as well as the metal-insulator transition in NbO2. We also used a nanoscale electron energy loss spectroscopy (EELS) thermometry technique we developed to demonstrate cooling in 2D Bi2Te3/Sb2Te3 thermoelectric coolers. The fabrication and imaging techniques reported here are broadly applicable and can be used to study virtually any nanoelectronic device in which operation alters the thermal or electronic state of the device.

  • 3 supplemental images
Cover page: Visualizing the Invisible in Functioning Nanoelectronic Devices
  • Article
  • Peer Reviewed
LBL Publications (2017)
The 2014-2016 JET results are reviewed in the light of their significance for optimising the ITER research plan for the active and non-active operation. More than 60 h of plasma operation with ITER first wall materials successfully took place since its installation in 2011. New multi-machine scaling of the type I-ELM divertor energy flux density to ITER is supported by first principle modelling. ITER relevant disruption experiments and first principle modelling are reported with a set of three disruption mitigation valves mimicking the ITER setup. Insights of the L-H power threshold in Deuterium and Hydrogen are given, stressing the importance of the magnetic configurations and the recent measurements of fine-scale structures in the edge radial electric. Dimensionless scans of the core and pedestal confinement provide new information to elucidate the importance of the first wall material on the fusion performance. H-mode plasmas at ITER triangularity (H = 1 at β N ∼ 1.8 and n/n GW ∼ 0.6) have been sustained at 2 MA during 5 s. The ITER neutronics codes have been validated on high performance experiments. Prospects for the coming D-T campaign and 14 MeV neutron calibration strategy are reviewed.
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