Browsing Τμήμα Μηχανικών Μηχανολογίας και Κατασκευαστικής / Department of Mechanical and Manufacturing Engineering by Author "Kanatzidis, M. G."

Now showing items 1-20 of 30

    • Article  

      A2Bi8Se13 (A = Rb, Cs), CsBi3.67Se6, and BaBi2Se4: New ternary semiconducting bismuth selenides 

      Iordanidis, L.; Brazis, P. W.; Kyratsi, Theodora; Ireland, J.; Lane, M.; Kannewurf, C. R.; Chen, W.; Dyck, J. S.; Uher, C.; Ghelani, N. A.; Hogan, T.; Kanatzidis, M. G. (2001)
      Rb2Bi8Se13 (I), Cs2Bi8Se13 (II), CsBi3.67Se6 (III), and BaBi2Se4 (IV) were synthesized by direct combination reactions of the A/Se (A = Rb, Cs, Ba) and Bi2Se3 at ≥650 °C. Their structures were determined by single-crystal ...
    • Article  

      Bi/Sb distribution and its consequences in solid solution members of the thermoelectric materials K2Bi8-xSbxSe13 

      Kyratsi, Theodora; Chung, D. Y.; Kanatzidis, M. G. (2002)
      In an effort to understand the nature of mass fluctuations introduced when β-K2Bi8Se13 is alloyed with K2Sb8Se13 we determined the detailed crystal structures of two solid solutions of the type K2Bi8-xSbxSe13 with x=4.0 ...
    • Conference Object  

      Carrier mapping in thermoelectric materials 

      Polymeris, G. S.; Hatzikraniotis, E.; Stefanaki, E. C.; Pavlidou, E.; Kyratsi, Theodora; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, GR- 54124, Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusAffiliation: Department of Chemistry, Northwestern University, 2145 North Sheridan Road, Evanston, IL 60208, United StatesCorrespondence Address: Physics Department, Aristotle University of Thessaloniki, GR- 54124, Thessaloniki, Greece, 2013)
      The application of micro-fourier transform infrared (FT1R) mapping analysis to thermoelectric materials towards identification of doping inhomogeneities is described. Micro-FTIR, in conjunction with fitting, is used as ...
    • Article  

      Crystal/glass phase change in KSb5S8 studied through thermal analysis techniques 

      Chrissafis, K.; Kyratsi, Theodora; Paraskevopoulos, K. M.; Kanatzidis, M. G. (2004)
      The reversible crystal-glass and glass-crystal transitions discovered in KSb5S8 were studied in detail with nonisothermal scanning calorimetry techniques. When cooled, molten KSb5S8 becomes a metastable glass, which can ...
    • Article  

      CsMBi3Te6 and CsM2Bi3Te7 (M = Pb, Sn): New thermoelectric compounds with low-dimensional structures 

      Hsu, K. F.; Chung, D. Y.; Lal, S.; Mrotzek, A.; Kyratsi, Theodora; Hogan, T.; Kanatzidis, M. G. (2002)
      The new materials CsPbBi3Te6 nad CsPb2Bi3Te7 were discovered through reactions of CsBi4Te6 with PbTe, whereas the isostructural materials CsSnBi3Te6 and CsSn2Bi3Te7 were discovered through corresponding reactions with SnTe. ...
    • Conference Object  

      Doping and alloying trends in new thermoelectric materials 

      Loo, S.; Lal, S.; Kyratsi, Theodora; Chung, D. Y.; Hsu, K. F.; Kanatzidis, M. G.; Hogan, T. P. (Affiliation: Dept. of Elec. and Comp. Engineering, Michigan State University, East Lansing, MI, United StatesCorrespondence Address: Loo, S.Dept. of Elec. and Comp. Engineering, Michigan State University, East Lansing, MI, United States, 2002)
      New thermoelectric bulk materials such as CsBi4Te6 have shown superior properties to traditional materials, however, optimal performance requires continuing investigations of doping and alloying trends. A recently modified ...
    • Conference Object  

      Doping studies of n-type CsBi4Te6 thermoelectric materials 

      Lane, M. A.; Ireland, J. R.; Brazis, P. W.; Kyratsi, Theodora; Chung, D. Y.; Kanatzidis, M. G.; Kannewurf, C. R. (Affiliation: Dept of Electrical and Computer Eng., Northwestern University, Evanston, IL 60208, United StatesCorrespondence Address: Lane, M.A.Dept of Electrical and Computer Eng., Northwestern University, Evanston, IL 60208, United States, 2001)
      We have previously reported the successful p-type doping of CsBi4Te6 which had a high figure of merit at temperatures below 300 K. In this study, several dopants were explored to make n-type CsBi4Te6. A program of measurements ...
    • Article  

      Electronic structure of K 2Bi 8Se 13 

      Bilc, D. I.; Mahanti, S. D.; Kyratsi, Theodora; Chung, D. Y.; Kanatzidis, M. G.; Larson, P. (2005)
      K 2Bi 8Se 13 belongs to a class of complex chalcogenides that shows potential for superior thermoelectric performance. This compound forms in two distinct phases, α and β. The β phase, which has several sites with mixed ...
    • Conference Object  

      FTIR Reflectivity spectra of Thermoelectric K2Sb 8Se13 crystals 

      Hatzikraniotis, E.; Hassapis, Th; Kyratsi, Theodora; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of CyprusAffiliation: Department of Chemistry, Michigan State University, MI 48824, United StatesCorrespondence Address: Hatzikraniotis, E.Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece, 2006)
      Investigations of ternary and quaternary compounds, Bi and Sb chalcogenides, have shown that several multinary compounds containing alkali metals present promising thermoelectric properties. In this work, the FTIR reflectivity ...
    • Article  

      Highly anisotropic crystal growth and thermoelectric properties of K 2Bi 8-xSb xSe 13 solid solutions: Band gap anomaly at low x 

      Kyratsi, Theodora; Dyck, J. S.; Chen, W.; Chung, D. Y.; Uher, C.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (2002)
      The thermoelectric properties of solid solutions of the type β-K 2Bi 8-xSb xSe 13 (0<x<8) were studied with respect to thermal behavior, band gap variation, and charge transport properties as a function of x. At x values ...
    • Conference Object  

      Initial assessment of the thermoelectric properties for the mixed system K2-xRbxBi8Se13 

      Ireland, J. R.; Kyratsi, Theodora; Kanatzidis, M. G.; Kannewurf, C. R. (Affiliation: Dept. of Elec. and Comp. Engineering, Northwestern University, Evanston, IL 60208-3118, United StatesCorrespondence Address: Ireland, J.R.Dept. of Elec. and Comp. Engineering, Northwestern University, Evanston, IL 60208-3118, United States, 2002)
      In previous studies we have investigated the thermoelectric properties of undoped and doped compositions of β-K2Bi8Se13. The attempt to substitute Rb for K resulted in a different structure type, but with potentially useful ...
    • Article  

      KSb5S8: A wide bandgap phase-change material for ultra high density rewritable information storage 

      Kyratsi, Theodora; Chrissafis, K.; Wachter, J.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (2003)
      The reversible glassformation and glass crystallization properties of KSb3S8 was described. On the basis of glass transition and crystallization kinetics of KSb5S8, it was found that the crystallization rate and assoicated ...
    • Article  

      Lattice thermal conductivity of K 2(Bi 1-zSb z) 8Se 13 solid solutions 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulous, M.; Dyck, J. S.; Shin, H. K.; Uher, C.; Kanatzidis, M. G. (2004)
      The influence of the Bi/Sb partial substitution to the lattice thermal conductivity of the K 2(Bi 1-zSb z) 8Se 13 solid solution series was studied. The variation of the lattice thermal conductivity with comparison was ...
    • Article  

      Local structure and influence of bonding on the phase-change behavior of the chalcogenide compounds K1-xRbxSb5S8 

      Wachter, J. B.; Chrissafis, K.; Petkov, V.; Malliakas, C. D.; Bilc, D. I.; Kyratsi, Theodora; Paraskevopoulos, K. M.; Mahanti, S. D.; Torbrügge, T.; Eckert, H.; Kanatzidis, M. G. (2007)
      KSb5S8 and its solid solution analogs with Rb and Tl were found to exhibit a reversible and tunable glass→crystal→glass phase transition. Selected members of this series were analyzed by differential scanning calorimetry ...
    • Conference Object  

      Mechanical alloying synthesis of K2Bi8Se 13- type solid solutions 

      Toumpas, N.; Kyratsi, Theodora; Hatzikraniotis, E.; Tsiappos, A.; Pavlidou, E.; Paraskevopoulos, K. M.; Chung, D. Y.; Kanatzidis, M. G. (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, 1678, CyprusAffiliation: Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124, GreeceAffiliation: Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, United StatesAffiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208, United StatesCorrespondence Address: Toumpas, N.Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, 1678, Cyprus, 2008)
      Solid solutions of β-K2Bi8-xSb xSe13 are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. In this work, we aimed ...
    • Conference Object  

      N-to-p transition on K2Bi8-xSbxSe 13 series 

      Kyratsi, Theodora; Hatzikraniotis, E.; Tsiappos, A.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusAffiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceCorrespondence Address: Kyratsi, Th.Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, Cyprus, 2006)
      β-K2Bi8Se13 and its solid solutions have been found to be interesting for thermoelectric investigations mainly due to their low thermal conductivity and highly anisotropic electrical properties. Solid solution series of ...
    • Conference Object  

      On the optical properties of thermoelectric alkali metal chalcogenide compounds 

      Hatzikraniotis, E.; Kyratsi, Theodora; Zorba, T.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusCorrespondence Address: Hatzikraniotis, E.Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece, 2006)
      Solid solutions of K2Bi8-xSbxSe 13 is an interesting series of complex bismuth-chalcogenide compounds, which are attractive for thermoelectric investigations. The highly anisotropic structure in these compounds results in ...
    • Article  

      Role of K/Bi disorder in the electronic structure of β -K2 Bi8 Se13 

      Hoang, K.; Tomic, A.; Mahanti, S. D.; Kyratsi, Theodora; Chung, D. Y.; Tessmer, S. H.; Kanatzidis, M. G. (2009)
      We have carried out tunneling spectroscopy and first-principles studies for β -K2 Bi8 Se13, a promising thermoelectric material with partially disordered mixed K/Bi sites. The tunneling data, obtained with a scanning ...
    • Article  

      Scanning tunneling microscopy of defect states in the semiconductor (formula presented) 

      Urazhdin, S.; Bilc, D. I.; Tessmer, S. H.; Mahanti, S. D.; Kyratsi, Theodora; Kanatzidis, M. G. (2002)
      Scanning tunneling spectroscopy images of (formula presented) doped with excess Bi reveal electronic defect states with a striking shape resembling clover leaves. With a simple tight-binding model, we show that the geometry ...
    • Article  

      Structure inhomogeneities, shallow defects, and charge transport in the series of thermoelectric materials K2Bi8-xSb xSe13 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Malliakas, C. D.; Dyck, J. S.; Uher, C.; Kanatzidis, M. G. (2006)
      The charge transport properties of the low-dimensional thermoelectric materials K2 Bi8-x Sbx Se13 (0<x≤8) were studied as a function of temperature and composition. The Seebeck coefficient shows an evolution from n - to p ...