Dr Knutt Muller
"Strain analysis from nano-beam electron diffraction patterns recorded on direct electron charge-coupled devices"
Biography:
Knut Müller studied physics at Bremen University where he turned to the field of electron microscopy in 2005 in a student research project on strain and composition in InGaN/GaN islands. In his diploma thesis he developed a Blochwave-based refinement program (Bloch4TEM) to measure low-order structure factors from electron spot diffraction patterns. In his PhD finished in 2011 he focused on the effects of bonding and static atomic displacements on electron diffraction patterns and HRTEM using ab-initio and empirical approaches. A HRTEM three-beam method was developed which exploits strain and chemically sensitive contrast to measure 2 chemical compositions in quaternary zinc-blende alloys. His post-doc activities concentrate on quantitative ADF-STEM Z-contrast simulations and experiments for composition quantification in semiconductor alloys. In his current project, strain is measured from large series of CBED patterns acquired in STEM mode with dedicated prototype high-speed detectors such as direct electron CCD or delayline detectors with kHz readout rate.