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SUMMARY:Time-Resolved Cathodoluminescence in an UTEM applied to III-V hete
 rostructures
DTSTART:20221116T120000
DTEND:20221116T130000
DTSTAMP:20260928T222637Z
UID:d91c79597f3a8530e79482364c18aeb3b4c00307d0987d9067f778ed
CATEGORIES:Conferences - Seminars
DESCRIPTION:Sophie Meuret \, Centre d’Élaboration de Matériaux et d
 ’Etudes Structurales (CEMES)\nThe development of time-resolved Cathodolu
 minescence (TR-CL) in a scanning electron microscope enabled the measureme
 nt of the lifetime of excited states in semiconductors with a sub-waveleng
 th spatial resolution. It was used for example to measure the influence of
  stacking faults on the GaN exciton 1\, to probe the role of a silver lay
 er on the dynamics of a YAG crystal 2 or to show the influence of stress
  on the optical properties of ZnO nanowires 3. These results demonstrate 
 that TR-CL is essential to study the correlation between semiconductor opt
 ical and structural properties (composition\, defects\, strain…). While 
 all these pioneering studies were done using a scanning electron microscop
 e\, the improvement of the spatial resolution and the combination with oth
 er electron-based spectroscopies offered by transmission electron microsco
 pes will be a step forward for TR-CL. We recently succeed to do the first 
 time-resolved cathodoluminescence experiments within an ultrasfast transmi
 ssion electron microscope. They were performed in a unique microscope\, ba
 sed on a cold-FEG electron gun 4. This technology allows among other thin
 gs to reach a spatial resolution of a few nanometres\, essential for the s
 tudy of III-V heterostructures.\nIn this presentation we will discuss our 
 latest results on InGaN quantum wells and discuss the unique features and 
 opportunities of this technique.\nReferences\n1.          Corfdir
 \, P. et al. Exciton localization on basal stacking faults in a-plane ep
 itaxial lateral overgrown GaN grown by hydride vapor phase epitaxy. J. Ap
 pl. Phys. 105\, 043102 (2009).\n2.          Moerland\, R. J.\, W
 eppelman\, I. G. C.\, Garming\, M. W. H.\, Kruit\, P. & Hoogenboom\, J. P.
  Time-resolved cathodoluminescence microscopy with sub-nanosecond beam bla
 nking for direct evaluation of the local density of states. Opt. Express
  24\, 24760 (2016).\n3.          Fu\, X. et al. Exciton Drift 
 in Semiconductors under Uniform Strain Gradients: Application to Bent ZnO 
 Microwires. ACS Nano 8\, 3412–3420 (2014).\n4.          Houde
 llier\, F.\, Caruso\, G. M.\, Weber\, S.\, Kociak\, M. & Arbouet\, A. Deve
 lopment of a high brightness ultrafast Transmission Electron Microscope ba
 sed on a laser-driven cold field emission source. Ultramicroscopy 186\, 
 128–138 (2018).
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418 https://epf
 l.zoom.us/j/68479474590?pwd=S21PdnpHNnpuSmhYeFJpdE44N1lDQT09
STATUS:CONFIRMED
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