A new TCAD simulation method for direct CMOS electron detectors optimization.

A custom CMOS image sensor hardened by design is characterized in a transmission electron microscope, with the aim to extract basic parameters such as the quantum efficiency, the modulation transfer function and finally the detective quantum efficiency. In parallel, a new methodology based on the combination of Monte Carlo simulation of electron distributions and TCAD simulations is proposed and performed on the same detector, and for the first time the basic parameters of a direct CMOS electron detector are extracted thanks to the TCAD. The methodology is validated by means of the comparison between experimental and simulation results.

Optimization of off-axis electron holography performed with femtosecond electron pulses.

We report on electron holography experiments performed with femtosecond electron pulses in an ultrafast coherent Transmission Electron Microscope based on a laser-driven cold field emission gun. We first discuss the experimental requirements related to the long acquisition times imposed by the low emission/probe current available in these instruments. The experimental parameters are first optimized and electron holograms are then acquired in vacuum and on a nano-object showing that useful physical properties can nevertheless be extracted from the hologram phase in pulsed condition.

Development of a high brightness ultrafast Transmission Electron Microscope based on a laser-driven cold field emission source.

We report on the development of an ultrafast Transmission Electron Microscope based on a cold field emission source which can operate in either DC or ultrafast mode. Electron emission from a tungsten nanotip is triggered by femtosecond laser pulses which are tightly focused by optical components integrated inside a cold field emission source close to the cathode. The properties of the electron probe (brightness, angular current density, stability) are quantitatively determined.

200 keV cold field emission source using carbon cone nanotip: Application to scanning transmission electron microscopy.

We report the use of a pyrolytic carbon cone nanotip as field emission cathode inside a modern 200 kV dedicated scanning transmission electron microscope. We show an unprecedented improvement in the probe current stability while maintaining all the fundamental properties of a cold field emission source such as a small angular current density together with a high brightness. We have also studied the influence of the low extraction voltage, as enabled by the nanosized apex of the cones, on the electron optics properties of the source that prevent the formation of a virtual beam cross-over of the gun.

Optimising electron microscopy experiment through electron optics simulation.

We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e.