Our group works in the study of the structure and physical properties of materials using transmission electron microscopy (TEM) under various operation imaging modes and electron diffraction including high resolution scanning and transmission electron microscopy (HRTEM, HRSTEM), aberration-corrected electron microscopy (Cs-corrected), off axis electron holography, low-dose TEM imaging, electron tomography, an others J. Appl. Phys 118 (2015) 024302.
Physical properties of materials (magnetic, electro-optic and mechanical) are studied under in-situ TEM experiments. Our work covers both, theory and experimental analyses, to finally study structure/physical property relationships based on the electron-matter phenomena and in situ TEM. Our group emphasizes the electron microscopy methods and post-processing via phase retrieval using off-axis electron holography. AIP Advances 8, (2018) 056813
Set of experimental STEM/NBD and simulated patterns extracted from the Au102(p‑MBA)44 cluster. Given an arbitrary orientation of the nanoparticle (c), a conical oscillation of the cluster is observed from the surrounding diffraction patterns (a, b, d, e), these one degree variations correspond to a “left, straight, right and back” tilting.
Our group has contributed in the structural determination of non-translational crystalline particles by scanning electron diffraction, precession electron diffraction and aberration-corrected microscopy. We have developed methodologies using electron diffraction for the determination of crystalline structure of metallic nanoclusters and the mapping of crystalline phases. These methods are based on electron diffraction using quasi-parallel illumination in aberration corrected scanning transmission electron microscopy (STEM) and crystal orientation phase mapping assisted by precession electron diffraction (PED). The latter in collaboration with NanoMEGAS company and CNRS in France to obtain virtual bright field images in multiple twined metallic polyhedral nanoparticles (Santiago et al, Surf. Sci. 644 (2016) 80). Using the scanning-PED method we have configured direct detection of electron diffraction patterns using an axial high sensitive CMOS camera (Ortega et al, Adv. Str. Ch. Im., 2:12 (2016) 1).
FUNDED PROJECTS
- Co-PI – Department of Defense (DOD) “Hybrid Plasmonics at UTSA: Investigating Plasmonic/Magnetic and Plasmonic/Biomolecular Systems” Awarded amount: $599,989 Period of support: 09/01/2018-08/31/2021. #W911NF-18-1-0439
- PI – Department of Defense (DOD) “Dual Beam System (SEM/FIB) Equipment for The Kleberg Advanced Microscopy Center”
#64756-RT-REP
Awarded amount: $500,000 Period of support: 02/14/2014-02/13/2015. - Co-PI National Science Foundation (NSF) “Alloys at the Nanoscale; The Case of Nanoparticles Second Phase”
#DMR-1103730, Awarded amount: $390,000 Period of support: 09/15/2011-08/31/2014. - Co-Director: Nanotechnology and Human Health Core
Research Centers in Minority Institutions (RCMI)-NIH
RCMI award number: 5 G12RR013646-12 - PI – CONACYT “Crystalline and structural defects in semiconductors materials by the using of the transmission electron microscopy combined with the precession electron diffraction” Award number: 103954, Period of support: 08/01/2009-07/31/2012.
- PI – CONACYT
Project title: Complementary support for the laboratory for electron microscopy
Awarded amount: 100,000 MXN (7,300 USD). Period of support: 08/01/2006-07/31/2007.
Microscopy Research Group 