Optical-Spectroscopy Group

Βrief Profile-History

The Condensed-Matter Optical-Spectroscopy Group is founded by the late Prof. E. Anastassakis, (beginning of  '80s), in the Physics Department of the National Technical University of Athens (now belonging to the School of Applied Mathematical and Physical Sciences, of the National Technical University of Athens , Zografou Campus, GR 157 80, GREECE)

For the past 40 years, optical studies and characterization research has been carried out in the Physics Department of the National Technical University of Athens (PD-NTUA) on a variety of materials such as semiconductors (Si, Ge, III-V, II-VI, chalcopyrites, chalcogenides, solar-cell materials), High-Tc  superconductors, Electrooptic crystals, tailor-made materials (heterostructures, superlattices, layered structures, quantum wells, etc.), porous silicon, amorphous semiconductors and glasses

The list of facilities at Phys. Dept.-NTUA, available to the optical spectroscopy group includes:

  • Thermo Fisher ESCALAB QXi XPS Microprobe for X-ray and ultraviolet photoelectron spectroscopy (XPS-UPS). Includes high-resolution imaging (down to <3 µm), ISS, REELS, dual anode and Ar+ ion and Ar+n cluster sputtering facilities. (To be installed during 2025).
  • Micro-Raman set-up including triple monochromator (Jobin-Yvon T64000) equipped with CCD Detection unit, PMT-option and microscope (spatial resolution 1μm).
  • Marqmetrix Process Raman Spectroscopy system with Raman probes (excitation at 785 nm).
  • FR-uProbe Thetametrisis system for measuring thickness and optical properties of films.
  • Several laser Units.
  • Both closed- and open-cycle He cryostats (4-300K).
  • High Temperature optical cell (300-1500 K).
  • Pressure Diamond Anvil Cell for high hydrostatic pressure (1 bar - 300 kbar) spectroscopic (Raman and/or PL) measurements in ambient temperature or low-temperature (80-300K).

Research

Based on the above mentioned equipment and their acquired experience, the optical spectroscopy group could study and provide results on:

  • Anharmonic behaviour and phase separation of dielectric, semiconducting and superconducting materials.
  • Strain characterization of materials, especially at the interfaces of tailor made or layered materials (Raman scattering), providing that the phonon deformation potentials (PDP) are known, or through their evaluation in the case of unknown-PDP's materials.
  • Assessment of degree of crystallinity and defects as well as structural variations of materials through Raman spectroscopy.
  • Spectroscopic analysis of perovskite halides and other materials for optoelectronic applications as well as for analysis of interactions of molecules adsorbed on metal organic frameworks or other porous materials.
  • Micro-Raman topography measurements across structural features and boundaries, and micro-Raman studies of micro-crystalline materials, at ambient conditions as well as under variable Temperature or Pressure.
  • Low Temperature photoluminescence measurements on bulk and low dimensional materials.
  • Measurements on biological materials (ex. cells and tissues) with advanced statistical analysis tools (PCA, Machine learning algorithms etc).
  • Surface stoichiometric and chemical analysis as well as study of the electronic properties of films and heterostructures.