National Institute Of Materials Physics - Romania

The lab has been created on 9^th September 2021 after the internal re-organisation of NIMP, by grouping scientists with related fields of interest and expertise in solid state physics and materials science.
Our research activity concerns mainly the physical properties – such as structure, optical, electrical and photoelectrical properties – in advanced materials, resulting either as size effects (nanostructures, thin films) or by engineering of structural defects. Although the size scale available through our investigation techniques spans from bulk to nanometric and atomic structures, our research is mainly directed towards the discovery, investigation and manipulation of physical properties at nanometric and atomic scale for the development and characterisation of new materials (dielectrics, semiconductors, alloys, ceramics) to be used in various applications (semiconductor technology, gas sensing, radiation detectors, telecommunications).

 Among the approached topics, we mention:

• Frontier research in condensed matter physics at nanoscale and in science of advanced materials of #structures with nanocrystals (NCs) based on SiGeSn and fstructures based on ferroelectric HfO₂, all structures being deposited by magnetron sputtering and also of materials and 2D heterojunctions based on transition metal dichalcogenides (2D-TMD):
  • study of optical, electrical, photoelectrical, ferroelectric and charge storage properties
  • strain and defects studies for improving the above mentioned properties
• Advanced materials for industry with global impact (fields of Eco-Nanotechnologies and Advanced Materials, Information and Communication Technology, Security, Energy, New and Emerging Technologies) for micro-, opto- and nanoelectronics applications and sensors for health, security and environment applications:
  • films and multilayered structures with NCs based on SiGeSn embedded in dielectric matrices (HfO₂, ZrO₂, SiO₂, TiO₂, Al₂O₃, Si₃N₄) photosensitive in SWIR, with ferroelectric and charge storage properties
  • HfO₂, ZrO₂ based structures with ferroelectric properties
  • 2D-TMD based materials and heterojunctions with electro-optic properties for health and environment applications
• applied research and experimental development for environment, security, space, health and internet of thing applications using the above mentioned materials (fields of Eco-Nanotechnologies and Advanced Materials, Information and Communication Technology, Security, Energy, New and Emerging Technologies); fabrication of devices – demonstrators up to TRL 5: electronic and photoelectric nonvolatile memories, dosimeters, optical sensors for monitoring the slippery road conditions (wet and icy in respect to dry asphalt), SWIR photodetectors, sensors for food security
• Investigations down to atomic scale by microstructural (TEM/HRTEM/STEM, XRD), spectroscopic (EPR, Mossbauer spectroscopy, EELS, EDS) and optical methods of native and induced defects in bulk and nanostructured solid materials.
• Investigations of material properties by using paramagnetic point defects as atomic probes.
• Investigations of the changes induced by defects in ordered and partially disordered solids.
• Synthesis of oxide semiconducting or magnetic nanostructures for applications in gas sensing, catalysis and photocatalysis.
• Hyperfine interactions in solids.
• Modelling of order-disorder transformations in crystalline media and transient phenomena in condensed matter.

A wide variety of investigation techniques and state-of-the-art equipments for materials synthesis, processing and characterization are available in our laboratory:

     Structural methods

• Analytical Transmission Electron Microscopy (TEM/HRTEM, STEM, EFTEM, EELS, EDS).
• Analytical Scanning Electron Microscopy and Focused Ion Beam (SEM-FIB, EDS, EBSD).
• Powder, thin film and single crystal X-ray diffraction (XRD).

     Spectroscopic methods

• Multifrequency Electron Spin/Paramagnetic Resonance (ESR/EPR) spectroscopy.
• Mössbauer spectroscopy (57Fe, 151Eu, 119Sn, TMS, SMS and CEMS) techniques.
• Optical spectroscopy (absorption and emission).

     Gas-sensing measurements

• Complex electrical measurements under controlled gas atmosphere for gas sensing (Gas Mixing Station).
• Gas-mixing installation.
• Catalytic investigations (Photo-acoustic gas analyzer).
• Relative work function investigations (Kelvin Probe).

     Electrical characterization (in dark and under illumination and Hall investigations by measurements and modelling of experimental curves)

     Materials synthesis

• Deposition of semiconductor thin films and multilayer structures by magnetron sputtering: dielectrics (SiO₂, TiO₂, ZrO₂, HfO₂, Al₂O₃, Si₃N₄) and semiconductors (Si, Ge, SiGe, SiGeSn) on heated substrates or on substrates mantained at room temperature
• Rapid thermal annealing (RTA) and controlled oxidations (RTO) in the rapid thermal processing – RTP system (up to 3-inch silicon wafer) at 200 – 1250 ^oC with ramp rates up to 200 ^oC/s, in gas flow (N₂, O₂, Ar si H₂) and thermal annealing in the three independent temperature zone horizontal split tube furnace at temperatures up to 1200 °C in vacuum or Ar, N₂ flow
• Single-crystal growth from melt (Czochralski, Bridgman).
• Preparation of nanocrystalline materials by co-precipitation, solvothermal method and high energy ball milling.