Group of Physics and Technology of Epitaxial Layers

Institute of Physics of the Polish Academy of Sciences

Welcome to the ON-1.2 group website

Our research group consists of one professor Tomasz Story (head of the group), one part-time assistant professor (Janusz Sadowski), two senior research assistants, three senior technical research assistants, six technical and technological staff, secretary, and three PhD students.

We are engaged in experimental research and technological activities in the field of physics of semiconductor and magnetic materials, in particular topological IV-VI narrow-gap semiconductors, thermoelectricity, and semiconductor spintronics.

Our main experimental expertise is with electric, thermoelectric, optical, magnetic, and structural properties of IV−VI, II–VI, and III\-V semiconductors. It, in particular, concerns our discoveries of: (1) carrier-induced ferromagnetism in IV-VI diluted magnetic (semimagnetic) semiconductor (Pb,Sn,Mn)Te and (2) topological crystalline insulator states in (Pb,Sn)Se.

Our current main research projects:

Topological crystalline insulators

  • Angle- and spin-resolved photoemission (ARPES) studies of Dirac topological states in (Pb,Sn)Se, (Pb,Sn,Mn)Se, and (Pb,Sn,Mn)Te
  • STM/STS experimental studies of electronic states along atomic steps on the surface of topological crystalline insulators
  • Quantum oscillations (Shubnikov–de Haas and de Haas–van Alphen effects) in bulk and surface electronic states of SnTe

Thermoelectric materials

  • Thermoelectric alloys based on (Pb,Sn,Mn)Te:Bi and (Pb,Sn)Te:Cr semiconductors
  • Thermoelectric bulk nanocomposites PbTe-CdTe:Bi,Na
  • Layered thermoelectric CdTe-PbTe crystalline nanocomposites

Semiconductor spintronics

  • Ferromagnetic transition and magnetic anisotropy of (Ge,Sn,Mn)Te and (Sn,Mn)Te layers with distorted crystal lattice
  • Magnetic properties of core/shell GaAs/(Ga,Mn)As nanowires

Semiconductor nanowires

  • Structural properties of core/shell (Ga,In)As/(Ga,Mn)As/(Ga,Al)As ferromagnetic nanowires on GaAs or Si substrates
  • MBE growth, structural and electric properties of topological SnTe nanowires

Infrared optoelectronic materials

  • Photoluminescence control in (Pb,Cd)Te/CdTe and (Pb,Cd)Se/CdSe quantum well and quantum dot structures by quantum size effect, strain, and band gap engineering

Highlights from our recent research (link)

Our technological facilities cover:

  • Self-selecting vapor phase growth (SSVG) of high quality monocrystals of IV-VI and II-VI semiconductors, e.g., PbTe, PbSe, PbS, SnTe, GeTe, (Pb,Sn)Se, (Pb,Sn)Te
  • Bridgman method of the growth from the melt of IV-VI semiconductor substitutional alloys for topological research, thermoelectricity, and spintronics, e.g., (Pb,Sn,Mn)Te, (Pb,Sn,Mn)Se, (Pb,Cd)Te, (Ge,Sn)Te, (Pb,Ge)Te, and Pb(Te,Se)
  • Molecular beam epitaxy (MBE) growth of IV-VI and II-VI multilayer nanostructures, e.g., (Pb,Sn)Te/CdTe quantum wells and quantum dots for infrared optoelectronics, quantum anti-dot CdTe/PbTe heterostructures for thermoelectricity, and (Ge,Sn,Mn)Te ferromagnetic layers for spintronics