ELECTRON MOBILITY IN GaAs1−<i>x</i>P<i>x</i> ALLOYS

Tietjen, J. J.; Weisberg, Leonard R.

doi:10.1063/1.1754248

Cited by 67 publications

(10 citation statements)

References 9 publications

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“…The effect coupled with thermal conductivity reduction in solid solutions is the mobility reduction due to the introduced alloy scattering of carriers, [65][66][67][68][69] the magnitude of which in the case of PbSe 1Àx S x at both 300 K and 850 K is shown in Fig. 3c.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric alloys between PbSe and PbS with effective thermal conductivity reduction and high figure of merit

Wang

Cao

et al. 2014

J. Mater. Chem. A

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The n-type alloys between PbSe and PbS are studied. The effect of alloy composition on transport properties is evaluated and the results are interpreted with theories based on random atomic site substitution. The alloying in PbSe 1Àx S x brings thermal conductivity reduction, carrier mobility reduction as well as change of effective mass. When all these factors are evaluated, both experimentally and theoretically, the optimized thermoelectric performance is found to change gradually with alloy composition. High zT can be found in all PbSe 1Àx S x alloys. The possibility of achieving significant improvement of zT through alloying is also discussed.

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Section: Introductionmentioning

confidence: 99%

Thermoelectric alloys between PbSe and PbS with effective thermal conductivity reduction and high figure of merit

Wang

Cao

et al. 2014

J. Mater. Chem. A

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“…In the second method, involving the theoretical calculation of p,, an additional scattering mechanism was added to those used in the GaSb analysis, viz, alloy scattering. There have been, in the past, various discussions of alloy scattering in these types of material (Ehrenreich 1959;Tietjen and Weisberg 1965;Coderre and Woolley 1969) with the general conclusion that, at most, alloy scattering will be a small effect in semiconductor alloys and will in many cases be negligible. Here, alloy scattering was represented by an energy dependent relaxation time z,,(E) given by where E, is the band gap, a, the lattice parameter, and k(E) and m*(E) the wave vector and effective mass of the electrons concerned.…”

Section: Theorymentioning

confidence: 98%

Electrical Transport Properties of Ga(As_xSb_1−x) and (Ga_xIn_1−x)Sb Alloys under Hydrostatic Pressure

Rosenbaum¹,

Woolley²

1975

Can. J. Phys.

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Del1ortt,7errt, Ut~i~jo.si?y of'0ttn11~ci. O t t t r u~~, Cotzodo Homogeneous polycrystalline n type samples of the alloys Ga (As,Sb, -, ) and (Ga,In, -,)Sb have been prepared from a stoichiometric melt by directional freezing methods. Room temperature measurements of electrical conductivity and Hall coefficient as a function of hydrostatic pressure up to 12 kbars have been made on samples of different composition by means of the van der Pauw technique, all specimens used in the measurements being carefully selected to avoid the presence of grain boundary effects. The experimental curves of conductivity and Hall coefficient as a function of pressure have been fitted to a two conduction band model with various band parameters taken as adjustable. The curves thus fitted give consistent values of El,, the energy separation of the two bands, as a function of x . For (Ga,ln,-,)Sb, the El, values are in good agreement with those obtained previously from measurements as a function of temperature, no previous values having been published for Ga (As,Sbl-,). Approximate values for the coupling coefficient Dl, of the alloys are also obtained.On a prepare a partir d'un melange stoichiometrique fondu, par des mkthodes de solidification directionnelle, des Cchantillons de type n, homogenes et polycristallins, d'alliages Ga(As,Sb,-,) et (Ga,In, -,)Sb. Des mesures a temperature ambiante de la conductivitk Clectrique et du coefficient de I'effet Hall, en fonction de la pression jusqu'a 12 kbars, ont CtC effectuees sur des echantillons de differentes compositions, au moyen de la technique de van der Pauw, les specimens utilises Ctant choisis avec soin pour tviter la presence d'effets de frontieres de grains. Les courbes experimentales de conductivitt et d'effet Hall ont permis de donner des valeurs aux parametres ajustables d'un modele a deux bandes de conduction. Cet ajustement a permis d'obtenir des valeurs coherentes pour El,, la difference d'knergie entre les deux bandes, en fonction de x. Pour (Ga,ln,-,)Sb, les valeurs de El, sont en bon accord avec celles qui ont ete obtenues anterieurement a partir de mesures en fonction de la temperature; pour Ga(As,Sbl -, ) il n'existe pas de valeurs publiees. On a aussi obtenu des valeurs approximatives de Dl,, le coefficient de couplage des alliages.[Traduit par le journal]Can. J. Phys.. S3,1071 (1975)

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“…However, such highly localized bound excitons related to isoelectronic centers strongly differ from the wide range of bound excitons known for shallow impurities in semiconductors and cannot be described by an effective mass approach [14][15][16]. The second class of isoelectronic centers (II) evokes the formation of mixed-crystal alloys like, e.g., SiGe [17], GaAsP [18,19], InGaAs [20], AlGaAs [21], InGaN [22], AlGaN [23,24], CdSSe [25,26], ZnSeTe [26], and MgZnO [27]. In these cases, no new electronic levels are formed in the band gap, but rather in the bands themselves, a process often described as hybridization [28].…”

Section: Introductionmentioning

confidence: 99%

Probing Alloy Formation Using Different Excitonic Species: The Particular Case of InGaN

2019

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Since the early 1960s, alloys are commonly grouped into two classes that feature either bound states in the band gap (I) or additional, nondiscrete band states (II). Consequently, one can observe either excitons bound to isoelectronic impurities or the typical band edge emission of a semiconductor that shifts and broadens with rising isoelectronic doping concentration. Microscopic parameters for class I alloys can directly be extracted from photoluminescence (PL) spectra, whereas any conclusions drawn for class II alloys usually remain limited to macroscopic assertions. Nonetheless, we present a spectroscopic study on exciton localization in a mixed-crystal alloy (class II) that allows us to access microscopic alloy parameters. In order to illustrate our approach, we study bulk In x Ga 1−x N epilayers at the onset of alloying (0 ≤ x ≤ 2.4%) in order to understand their robustness to point and structural defects. Through an indepth PL analysis it is demonstrated how different excitonic complexes (free, bound, and complex bound excitons) can serve as a probe to monitor the dilute limit of class II alloys. From an x-dependent linewidth analysis we extract the length scales at which excitons become increasingly localized, i.e., their conversion from a free to a bound particle upon alloy formation. Already at x ¼ 2.4% the exciton diffusion length is reduced to 5.7 AE 1.3 nm at a temperature of 12 K; hence, detrimental exciton transfer mechanisms toward nonradiative defects are suppressed. In addition, the associated low-temperature PL data suggest that a single indium atom cannot permanently capture an exciton. The low density of silicon impurities in our samples even allows studying their local indium-enriched environment at the scale of the exciton Bohr radius based on impurity bound excitons. The associated temperature-dependent PL data reveal an alloying dependence for the exciton-phonon coupling. Thus, the formation of the random alloy can not only be monitored by the emission of various excitonic complexes, but also more indirectly via the associated coupling(s) to the phonon bath. Micro-PL spectra even give access to a probing of silicon bound excitons embedded in a particular environment of indium atoms thanks to the emergence of a series of individual and energetically sharp emission lines (full width at half maximum ≈300 μeV). Consequently, the present study allows us to extract microscopic properties formerly mostly only accessible for class I alloys.

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ELECTRON MOBILITY IN GaAs1−xPx ALLOYS

Cited by 67 publications

References 9 publications

Thermoelectric alloys between PbSe and PbS with effective thermal conductivity reduction and high figure of merit

Thermoelectric alloys between PbSe and PbS with effective thermal conductivity reduction and high figure of merit

Electrical Transport Properties of Ga(As_xSb_1−x) and (Ga_xIn_1−x)Sb Alloys under Hydrostatic Pressure

Probing Alloy Formation Using Different Excitonic Species: The Particular Case of InGaN

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ELECTRON MOBILITY IN GaAs1−xPx ALLOYS

Cited by 67 publications

References 9 publications

Thermoelectric alloys between PbSe and PbS with effective thermal conductivity reduction and high figure of merit

Thermoelectric alloys between PbSe and PbS with effective thermal conductivity reduction and high figure of merit

Electrical Transport Properties of Ga(AsxSb1−x) and (GaxIn1−x)Sb Alloys under Hydrostatic Pressure

Probing Alloy Formation Using Different Excitonic Species: The Particular Case of InGaN

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Electrical Transport Properties of Ga(As_xSb_1−x) and (Ga_xIn_1−x)Sb Alloys under Hydrostatic Pressure