Analysis of Lattice and Ionized Impurity Scattering in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi></mml:math>-Type Germanium

Brown, D.M.; Bray, Ralph

doi:10.1103/physrev.127.1593

Cited by 181 publications

(36 citation statements)

References 26 publications

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“…31 The value of μ NA then decreased with decreasing T as a function of T 1.5 for 300 K > T > 190 K because of ionized-defect scattering. Even at 300 K, μ NA was effected by ion scattering, indicating a high concentration of ionized defects in the Ge film.…”

Section: Resultsmentioning

confidence: 99%

Sputter Epitaxial Growth of Flat Germanium Film with Low Threading-Dislocation Density on Silicon (001)

Yeh

Matsumoto

Sugihara

et al. 2014

ECS J. Solid State Sci. Technol.

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Fast epitaxy of Ge on Si(001) was realized by DC sputtering at 2.1 nm · s −1 and 360 • C; the resulting film was optically flat without a cross-hatch structure. After annealing at 700 • C, 90 • -full-edge dislocations dominated the Ge-Si interface and the threadingdislocation density (TDD) of the Ge film was below 10 4 cm −2 , which is three orders of magnitude lower than the value of Ge films prepared by other methods. The extremely low TDD might be attributable to the spaces vacated by desorbed Ar within the film that served as dislocation sinks during sputtering. Acceptor-band conduction, which was at 0.02 eV above the valence band and was induced by dislocations, was observed with a hole mobility of 3-10 cm 2 · V −1 · s −1 in the film prepared without annealing. After annealing at 700 • C, the ionized-defect scattering in the film was considerably decreased and a mobility of 1180 cm 2 · V −1 · s −1 was obtained. The direct band gap energy of the film prepared without annealing was 0.81 eV, and became 0.79 eV after annealing.

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Section: Resultsmentioning

confidence: 99%

Sputter Epitaxial Growth of Flat Germanium Film with Low Threading-Dislocation Density on Silicon (001)

Yeh

Matsumoto

Sugihara

et al. 2014

ECS J. Solid State Sci. Technol.

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“…(3), where r ¼ 0:0 and À1:0 represents scattering by acoustic phonons and the interaction between acoustic and optical phonon scattering, respectively. [20][21][22] From the slope of the H -T curves, r values for the MA and VBM-HPT samples were estimated to be À1:3 and +0.1, respectively. The scattering mechanism of the VBM-HPT sample was due to acoustical phonons while that of the MA sample was attributed to the interaction between acoustical and optical phonons.…”

Section: Resultsmentioning

confidence: 99%

“…The scattering mechanism of the VBM-HPT sample was due to acoustical phonons while that of the MA sample was attributed to the interaction between acoustical and optical phonons. 21,22) Figure 6 shows plots of the Seebeck coefficient versus temperature for the MA and VBM-HPT samples. The Seebeck coefficient of the MA sample was larger than that of the VBM-HPT sample at around 300 K. These results were consistent with the fact that the absolute r value of the MA sample is larger than that of the VBM-HPT sample according to eq.…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric Properties of Bi2Te3-Related Materials Finely Grained by Mechanical Alloying and High Pressure Torsion

et al. 2009

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Bi 2 Te 3 -related thermoelectric semiconductors were prepared by the mechanical alloying (MA) and the vertical Bridgman (VBM)-High Pressure Torsion (HPT) methods. Structures and electric properties of these alloys were then investigated. These samples had a nominal composition of Bi 0:5 Sb 1:5 Te 3:0 with 0.07 mass% excess Te. The MA sample was sintered into a compact after mechanical alloying while the VBM-HPT sample was deformed by HPT after being cut into a disk from a melt-grown ingot by the vertical Bridgman method (VBM). The orientation factors of the MA and VBM-HPT samples were 0.054 and 0.525, respectively, indicating that the preferred orientation was formed by VBM-HPT. Average grain sizes of both samples were approximately 2 mm. The VBM-HPT sample was shown low electrical conductivity than the MA one in spite of the high orientation factor.By estimating the slope of carrier mobility versus temperature the carrier scattering factor of the MA and VBM-HPT samples were estimated to be À1:3 and +0.1. These values are indicative of carrier scatterings by acoustic phonons and by the interaction between acoustic and optical phonons, respectively. The maximum power factor obtained for the isotropic MA sample was 4:1 Â 10 À3 W m À1 K À2 at 310 K and this was about twice the 2:1 Â 10 À3 W m À1 K À2 at 440 K obtained for the anisotropic VBM-HPT sample.

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“…16,17) This type of high scattering factor has been reported for a crystal with a low carrier concentration (n ¼ $ 10 23 m À3 ) which was prepared by melt growth.…”

Section: Resultsmentioning

confidence: 99%

Thermoelectric Properties and Scattering Factors of Finely Grained Bi2Te3-Related Materials Prepared by Mechanical Alloying

et al. 2010

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Fine grained samples with a nominal composition of Bi 0:5 Sb 1:5 Te x (x ¼ 3:0 to 3.4) were prepared by mechanical alloying (MA). Average grain sizes were found to range from 1.0 to 2.1 mm. Tellurium precipitation at x ¼ 3:1 was observed by scanning electron microscopy (SEM), Xray diffraction and differential thermal analysis (DTA). Electrical conductivity as well as Hall and Seebeck coefficients were measured from 300 to 470 K. Using the relationship between Hall mobility and temperature, carrier scattering factors of the Bi 0:5 Sb 1:5 Te x samples were estimated to range from r ¼ À0:9 to À2:0. The thermal conductivities of the samples were found to range from 0.94 to 1.00 Wm À1 K À1 at room temperature. Excess tellurium was recognized to be responsible for the decrease in thermal conductivity. The Lorenz number and the carrier component of thermal conductivity were calculated from the scattering factor and the Fermi integral. The phonon component of thermal conductivity was dominant in the Bi 0:5 Sb 1:5 Te x samples. The Seebeck coefficient of the Bi 0:5 Sb 1:5 Te x samples was higher than that from the available data which means that the absolute scattering factor of the Bi 0:5 Sb 1:5 Te x samples was large. A maximum figure of merit of 7:02 Â 10 À3 K À1 was obtained at 310 K for the Bi 0:5 Sb 1:5 Te 3:1 sample. This high figure of merit results from an enhanced Seebeck coefficient that is due to an increased absolute scattering factor. High thermoelectric performance can, therefore, be established by a reduction in the phonon component of the thermal conductivity and also by an enhanced Seebeck coefficient, which results from an increased absolute scattering factor for finely grained Bi 0:5 Sb 1:5 Te x samples that were prepared by MA.

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Analysis of Lattice and Ionized Impurity Scattering inp-Type Germanium

Cited by 181 publications

References 26 publications

Sputter Epitaxial Growth of Flat Germanium Film with Low Threading-Dislocation Density on Silicon (001)

Sputter Epitaxial Growth of Flat Germanium Film with Low Threading-Dislocation Density on Silicon (001)

Thermoelectric Properties of Bi<SUB>2</SUB>Te<SUB>3</SUB>-Related Materials Finely Grained by Mechanical Alloying and High Pressure Torsion

Thermoelectric Properties and Scattering Factors of Finely Grained Bi<SUB>2</SUB>Te<SUB>3</SUB>-Related Materials Prepared by Mechanical Alloying

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