Brief 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 , Zogrfou Campus, GR 157 80, GREECE).
For the past 30 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 (hetrostructures, superlattices, layered structures, quantum wells, etc.), porous silicon, amorphous semiconductors and glasses.

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

• Complete system for macro-Raman (and/or Luminescence) measurements, with double monochromator (SPEX 1403) plus PMT and photon counting unit.
• Micro-Raman set-up including triple monochromator (Jobin-Yvon T64000) equipped with CCD Detection unit, PMT-option and microscope (spatial resolution 1μm).
• Several laser Units (Ar+,, Kr+, dye, cw-Ti:sapphire).
• Both closed- and open-cycle He cryostats (4-300K).
• High Temperature optical cell (300-1500 K)
• for piezo-Raman (or PL) uniaxial stress experiments (1-10 bar).
• 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 crystalinity and defects as well as structural variations of materials through Raman spectroscopy.
• 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.