Showing papers on "Lead telluride published in 2004"
TL;DR: In this article, n-type lead telluride (PbTe) compounds without doping were sucessfully prepared at high pressure and high temperature (HPHT), where the carrier type was induced by the effect of pressure.
Abstract: In this paper, n-type lead telluride (PbTe) compounds without doping were sucessfully prepared at high pressure and high temperature (HPHT). The carrier type was induced by the effect of pressure. The results of the electrical conductivity, Seebeck coefficient, thermal conductivity for n-type PbTe, which were measured at room temperature, show that the PbTe samples prepared by HPHT exhibit the same characteristics as heavily doped semiconductors. The figure-of-merit, Z ,o f5:46 � 10 � 4 K � 1 was obtained, which is higher than the heavily doped samples of PbTe at room temperature. These results indicate that this method has potential application in obtaining good quality thermoelectric materials with improved properties.
45 citations
TL;DR: A review of recent results of experimental investigations devoted to studying unusual properties of impurity states in doped narrow-gap lead telluride-based semiconductors is presented in this article.
Abstract: A review of recent results of experimental investigations devoted to studying unusual properties of impurity states in doped narrow-gap lead telluride-based semiconductors is presented. These results are analyzed in the framework of existing theoretical concepts.
25 citations
TL;DR: In this paper, the authors describe the ballistic transport in nanostructures of lead telluride, PbTe, and show that the huge static dielectric constant of Pbte leads to suppression of the long-range Coulomb potentials of charged impurities and thus provides favorable conditions for the conductance quantization.
Abstract: We describe our study of ballistic transport in nanostructures of lead telluride, PbTe. Submicron devices have been fabricated by electron beam lithography and chemical etching of 50 nm wide PbTe single quantum wells embedded between Pb 0.92 Eu 0.08 Te barriers grown by MBE on BaF 2 . The electron concentration in the devices was tuned by the gate voltage applied across an interfacial p–n junction. The most important observation was zero-magnetic field conductance quantization (in multiplies of 2 e 2 / h ) in narrow constrictions of dimensions comparable to electron mean free path calculated from transport mobility. This indicates considerable relaxation of requirements for quantum ballistic transport in comparison with other materials. We argue that the huge static dielectric constant of PbTe ( e 0 =1350 at 4.2 K ) leads to suppression of the long-range Coulomb potentials of charged impurities and, thus, provides favorable conditions for the conductance quantization.
19 citations
Patent•
03 Nov 2004
17 citations
TL;DR: In this paper, the role of minority carriers in degrading the thermoelectric properties of lead telluride was investigated and the utility range of the material was determined by the degrading effect of minority carrier conduction.
Abstract: Usefulness of a material in thermoelectric devices is temperature specific. The central problem in thermoelectric material research is the selection of materials with high figure-of-merit in the given temperature range of operation. It is of considerable interest to know the utility range of the material, which is decided by the degrading effect of minority carrier conduction. Lead telluride is among the best-known materials for use in the temperature range 400–900 K. This paper presents a detailed theoretical investigation of the role of minority carriers in degrading the thermoelectric properties of lead telluride and outlines the temperature range for optimal performance.
10 citations
TL;DR: In this paper, a Pb0.75Sn0.25Te(In) alloy initiated by monochromatic submillimeter-range radiation at wavelengths of 176 and 241 µm was observed at helium temperatures.
Abstract: Persistent photoconductivity in a Pb0.75Sn0.25Te(In) alloy initiated by monochromatic submillimeter-range radiation at wavelengths of 176 and 241 µm was observed at helium temperatures. This photoconductivity is shown to be associated with optical excitation of metastable impurity states.
7 citations
TL;DR: In this article, the gallium-induced defects in PbTe-GexTe and Pb1−ySnyTe were investigated and the results showed that the alloys possess high infrared photosensitivity at temperatures below Tc = 50-60 K.
Abstract: Galvanomagnetic and photoelectric properties of the Pb1−ySnyTe (0 ≤ y ≤ 0.06) and Pb1−xGexTe (0.04 ≤ x ≤ 0.08) single crystals doped with gallium (CGa = 0.3–3 mol%) have been investigated. Low-temperature activation ranges of the impurity conductivity on the dark curves of the resistivity ρ(1/T) and Hall coefficient RH(1/T) were revealed and attributed to the appearance of gallium-induced deep levels in the gap of the alloys. It was shown that the alloys possess high infrared photosensitivity at temperatures below Tc = 50–60 K. The results are discussed in the frame of the model assuming that doping with gallium leads to the formation of two different gallium-related defect levels in the energy spectrum of the PbTe-based alloys. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
6 citations
TL;DR: In this article, physical principles of operation of the photodetecting devices based on the group III doped IV-VI including possibilities of fast quenching of the persistent photoresponse, construction of a focalplane array, new readout technique, and others.
Abstract: Doping of the lead telluride and related alloys with the group III impurities results in the appearance of unique physical features of the material, such as persistent photoresponse, enhanced responsive quantum efficiency (up to 100 photoelectrons/incident photon), radiation hardness and many others. We review physical principles of operation of the photodetecting devices based on the group III doped IV–VI including possibilities of fast quenching of the persistent photoresponse, construction of a focal-plane array, new readout technique, and others. Comparison of performance of the state of the art Ge(Ga) and Si(Sb) photodetectors with their lead telluride based analogs shows that the responsivity of PbSnTe(In) photodetectors is by several orders of magnitude higher. High photoresponse is detected at the wavelength of 241 μm in PbSnTe(In), and it is possible that the photoconductivity spectrum covers all the submillimeter wavelength range.
5 citations
Journal Article•
TL;DR: In this paper, single crystal samples of lead telluride doped with samarium were produced using the Bridgman method and numerically analyzed using a fitting procedure based on a modified plasmon-phonon interaction model.
Abstract: Single crystal samples of lead telluride doped with samarium were produced using the Bridgman method. Far infrared reflectivity spectra in the temperature range 10 K - 300 K are presented and numerically analyzed using a fitting procedure based on a modified plasmon-phonon interaction model. The optical parameters were determined and three local modes of samarium were observed at about 167 cm - 1 , 227 cm - 1 and 486 cm - 1 .
4 citations
TL;DR: In this article, a crystal-quasi-chemical model is proposed for defect formation in PbTe〈In〉: the incorporation of In+ into octahedral interstices and In3+ into tetrahedral inter stices of the close packing of Te atoms, accompanied by In2Te3 precipitation.
Abstract: Experimental data on the lattice parameter, thermoelectric power, and microhardness of PbTe〈In〉 crystals and the conversion fromp- to n-type with increasing indium content can be interpreted under the assumption that the indium in PbTe〈In〉 has variable valence: 2In2+ ↔ In+ + In3+. A crystal-quasi-chemical model is proposed for defect formation in PbTe〈In〉: the incorporation of In+ into octahedral interstices and In3+ into tetrahedral interstices of the close packing of Te atoms, accompanied by In2Te3 precipitation.
3 citations
TL;DR: In this article, the impedance of single-crystal PbTe:Ga and Pb0.94Ge0.06Te:Ge samples was studied in the frequency range from 102 to 106 Hz at temperatures of 4.2 to 300 K. It was shown that the effects associated with longterm relaxation processes do not result from a ferroelectric phase transition, because they are observed at much lower temperatures.
Abstract: The impedance of single-crystal PbTe:Ga and Pb0.94Ge0.06Te:Ga samples was studied in the frequency range from 102 to 106 Hz at temperatures of 4.2 to 300 K. It was shown that the effects associated with long-term relaxation processes do not result from a ferroelectric phase transition, because they are observed at much lower temperatures. The low-temperature features of the behavior of the capacitance in Pb0.94Ge0.06Te:Ga are regarded as a contribution from the impurity subsystem.