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- 1. Appl. Phys. Lett. 90, 122103 (2007) , American Institute of Physics , “Pressure-tuned colossal improvement of thermoelectric efficiency of PbTe”, Sergey V. Ovsyannikov and Vladimir V. ShchennikovThe variations in thermoelectric (TE) efficiencies æ of lead chalcogenide compounds (p-PbTe, n-PbTe, p-Pb0.55Te0.45, p-Pb1−xSnxTe1−y, p-PbSe, and p-PbS) at room... (Read more)
- 2. phys. stat. sol. (b) 244, 437 (2007) , Wiley InterScience , “Thermoelectric properties and phase transitions of II-VI semiconductors at ultrahigh pressure”, V.V. Shchennikov, S.V. OvsyannikovThe high-pressure phase transitions in II-VI semiconductors (HgTe, HgSe, HgS, HgO, CdTe, CdSe, CdS, ZnTe, ZnSe, ZnS, ZnO) are analyzed in light of recent findings. A contribution is emphasized of the thermoelectric power (Seebeck effect) technique to registration of new electronic phases and to... (Read more)
- 3. J. Phys.: Condens. Matter 18, L551 (2006) , IOP Publishing , “Observation of a new high-pressure semimetal phase of GaAs from pressure dependence of the thermopower”, S.V. Ovsyannikov, V.V. ShchennikovWe report the use of the thermopower technique (Seebeck effect) as an effective tool for discovery of 'hidden' (for standard techniques, like x-ray, synchrotron, Raman, etc) phases of substances. Applying the thermopower technique to a set of GaAs single crystals pressurized in a sintered diamond... (Read more)
- 4. Physica B 376-377, 177 (2006) , Elsevier , “Micro-characterisation of Si wafers by high-pressure thermopower technique”, S.V. Ovsyannikov, V.V. Shchennikov Jr, N.A. Shaydarova, V. V. Shchennikov, A. Misiuk, D. Yang, I.V. Antonova, S.N. ShaminIn the present work a set of Czochralski-grown silicon wafers (Cz–Si) differently pre-treated (annealed at high temperatures in pressure medium, doped with nitrogen, implanted with high-energy hydrogen ions) has been characterised by high-pressure thermopower S technique in the phase transitions region (0-20GPa). The shifts were observed in pressure of semiconductor–metal phase transition Pt determined from the S(P) under pre-treatments. For the first time, correlation dependence has been established between high-pressure thermoelectric properties on the one hand and concentration of residual interstitial oxygen cO (which is always present in Cz–Si) on the other hand. The dependence exhibited a maximum of Pt near cO~9×1017cm-3. (Read more)
- 5. J. Phys.: Condens. Matter 17, S3179 (2005) , IOP Publishing , “Phase transitions in PbSe under actions of fast neutron bombardment and pressure”, S.V. Ovsyannikov, V.V. Shchennikov, A.E. Kar’kin, B.N. GoshchitskiiIn this paper, the influences of fast neutron bombardment, high pressure and chemical substitution on the electronic properties of PbSe single crystals are studied. For the first time in p-PbSe an electronic transition has been established of 'metal–semiconductor' type accompanied by an... (Read more)
- 6. phys. stat. sol. (b) 241, 3242 (2004) , WILEY-VCH , “Influence of P-T pre-treatment on thermopower of Czochralski-grown silicon at high pressure”, V.V. Shchennikov, S.V. Ovsyannikov, A. Misiuk, V.V. Shchennikov JrFor the first time the thermoelectric power of high-pressure phases of Czochralski-grown silicon (Cz-Si) single crystals has been investigated. From the dependence on pressure of the thermopower the phase transitions in Si have been established. The influence of gas pressure (up to 1.5 GPa) and... (Read more)
- 7. Physica B 344, 190 (2004) , Elsevier , “Thermomagnetic and thermoelectric properties of semiconductors (PbTe, PbSe) at ultrahigh pressures”, S.V. Ovsyannikov, V.V. ShchennikovThe longitudinal and transverse thermomagnetic Nernst–Ettingshausen (LNE, TNE) effects and the Maggi–Reghi–Leduc (MRL) effect were measured on PbTe and PbSe micro-samples at ultrahigh pressures upto 20 GPa. Values of the mobility of charge carriers as well as the scattering parameter were estimated both for the low- and high-pressure phase of PbTe and PbSe. At about 3 GPa, the maxima of both Nernst–Ettingshausen effects and magnetoresistance (MR) (and hence of the mobility of charge carriers μ), attributed to the gapless state of PbTe and PbSe were established. The TNE effect was found to be the largest among the effects measured, while the MRL was hardly visible even at the highest mobility values of the charge carriers. The possibilities for using thermomagnetic effects in micro-device technologies are discussed. (Read more)
- 8. Solid State Commun. 132, 545 (2004) , Pergamon Press , “Pressure-induced phase transitions in Si observed by thermoelectric power measurements”, S.V. Ovsyannikov, V.V. Shchennikov, A. Misiuk, V.V. Shchennikov JrFor the first time the phase transitions under high pressure P up to 20 GPa have been observed in Czochralski-grown Si single crystals by thermoelectric power S measurements. Values of S≈+8±3 μV/K have been determined for tetragonal, orthorhombic and simple hexagonal high-pressure phases. The behaviour of S(P) was found to be rather different for different Si samples—initial and pre-treated by high temperatures 450–650ºC under hydrostatic pressure 0–1.5 GPa. (Read more)
- 9. Solid State Commun. 132, 333 (2004) , Pergamon Press , “Phase transitions investigation in ZnTe by thermoelectric power measurements at high pressure”, S.V. Ovsyannikov, V.V. ShchennikovThe pressure-induced phase transitions were studied in ZnTe by the thermoelectric power (S) technique. For the high-pressure trigonal phase P3121 cinnabar the large thermopower values S≈+400 correspond to semiconductor hole conductivity. During a transition into the orthorhombic structure Cmcm the value of S dropped by 40–50 times indicating metallic hole conductivity, like in the high pressure phases of other chalcogenides of II Group (HgSe, HgTe, CdTe) with Cmcm structure. In a transient region between the trigonal and orthorhombic phase (especially under decreasing pressure) a novel phase has been observed with a negative value of S. By analogy with other Zn and Cd chalcogenides whose NaCl phases have an electron type of conductivity the phase observed may have a NaCl structure. (Read more)
- 10. Solid State Commun. 126, 373 (2003) , Pergamon Press , “Thermoelectric power, magnetoresistance of lead chalcogenides in the region of phase transitions under pressure”, V.V. Shchennikov, S.V. OvsyannikovThe longitudinal and transverse thermomagnetic Nernst–Ettingshausen (N–E) effects were measured at ultrahigh pressure up to 20 GPa under closure of semiconductor gap at NaCl- and GeS-type phases of n-PbTe, p-PbSe and p-PbS. Near~3 GPa, the maxima of N–E effects and magnetoresistance (and hence of mobility of charge carriers) attributed to gapless state for PbTe and PbSe were established. The reversible sign inversion of transverse N–E effect indicating the change in scattering mechanism of charge carries have been revealed at high pressure phase of PbSe. The lowering of thermomagnetic effects with pressure gave the evidence of indirect semiconductor gap at high pressure GeS-type phases in contrary to NaCl-phases. (Read more)
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