Ordered structures in GaAs0.5Sb0.5 alloys grown by organometallic vapor phase epitaxy

Jen, H. R.; Cherng, M. J.; Stringfellow, G. B.

doi:10.1063/1.96830

Cited by 242 publications

(38 citation statements)

References 14 publications

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“…In particular, we account for the growth of only two orientations of (111) MSL's (reported for all systems investigated so far), and of only one (110) BSL variant (reported for GaΡ/InΡ [11]). Further, ΔΕsu r for (100) and (111) MSL's are close to each other, which may explain the growth of both phases reported for GaΑs0.5Sb0.5 [12,13]. On the other hand, high ordering of Ga0.51n0.5Ρ in the phase of (111) MSL occurring for high growth temperatures is not explained by the present approach, and is possibly due [8] to the presence of monolayer steps at the surface.…”

mentioning

confidence: 47%

Surface Stability of Ordered Ga_0.5In_0.5P and GaAs_0.5Sb_0.5Alloys

Bogusławski¹

1991

Acta Phys. Pol. A

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Formation enthalpies of (001) surfaces terminating ordered Ga0.5ln0.5P and GaAs0.5Sb0.5 alloys were calculated using the VFF model. For several ordered phases, chemically ordered surfaces were found to be stable against surface segregation. In particular, even phases unstable against bulk segregation may be terminated by a stable surface.PACS numbers: 68.65.+g, 68.60.Dv, 61.55.Hg Thermodynamic stability has recently been investigated theoretically for several ordered lattice-mismatched alloys [1][2][3][4]. It was found that both (001) and (111) lattice-mismatched monolayer superlattices (MSL's) are intrinsically unstable at T = 0, and should segregate into pure end compounds. The instability of these systems persists even when the epitaxial stabilization is taken into account. As it was shown in [1], the instability is due to the excess elastic energy of bonds distorted by the lattice misfit.In the above context, the unintentional growth of both (001) and (111) lattice-mismatched MSL's is unexplained. Epitaxial growth of these phases has been recently reported for several III-V alloys [5]. The most frequent form of ordering, reported for all systems investigated so far, is a (111)-oriented MSL. On the other hand, the theory indicates that this phase is more unstable than both the (100) MSL and the random phase. Its metastability was confirmed experimentally [7]. One should observe, however, that the previous theoretical approaches neglected active role of the surface processes in epitaxy.In particular, it was suggested [8] that the growth of an ordered epitaxial alloy originates in a 2D ordering of atoms at the surface during growth. This, in turn, may be driven by the stability of chemically ordered surfaces. To verify this possibility, we have investigated surface stability against 2D segregation at T = 0, which is given by the surface formation enthalpy (125)

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confidence: 47%

Surface Stability of Ordered Ga_0.5In_0.5P and GaAs_0.5Sb_0.5Alloys

Bogusławski¹

1991

Acta Phys. Pol. A

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“…It is worth noting that other authors have seen fairly large discrepancies of up to 0.2 eV in the PL energies compared with predictions obtained using tabulated values of the bowing parameters [15]. We have also performed TEM measurements on these samples, which showed ordering in these quaternary material similar to the Cu-Au type observed in GaAsSb [16,17]. Recent PL measurements on GaAsSb ternary alloys indicated that the presence or absence of strong Cu-Au ordering had no effect on the PL energies [17].…”

Section: Resultsmentioning

confidence: 78%

Optical and electrical characterization of OMVPE-grown AlGaAsSb epitaxial layers on InP substrates

Rao

Jiang

et al. 2006

Journal of Crystal Growth

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“…Strong bowing indicates a large change in lattice energy, which acts as a driving force for ordering, that is, for compound formation when a stoichiometric atomic ratio is reached rather than the formation of a statistical alloy. Examples are SiGe, GaInP 2 , or Ga 2 AsP (Jen et al 1986;Srivastava et al 1986;Ourmazd and Bean 1985). For In x Ga 1-x N and In x Al 1-x N alloys, see Ferhat and Bechstedt (2002).…”

Section: Bandgap Of Alloysmentioning

confidence: 99%

Bands and Bandgaps in Solids

Böer

Pohl

2014

Semiconductor Physics

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Valence and conduction bands and the bandgap in between these bands determine the electronic properties of solids. For semiconductors, the band structure of the conduction band and the valence bands near the edge to the fundamental bandgap is of particular interest. Both the band structure and bandgap are influenced by external parameters such as temperature and pressure and can also be changed by alloying and heavy doping.In low-dimensional semiconductors like superlattices and quantum wells, quantum wires and quantum dots anisotropic carrier confinement occurs. The effective gap and energies in conduction and valence bands can be varied by changing spatial dimensions and barrier height of the low-dimensional structure. The bands in amorphous semiconductors near the band edge are ill-defined since long-range periodicity is missing. Still the density-of-state distribution shows significant similarities to that of the same material in the crystallite state. Valence and Conduction BandsThis chapter outlines the most important bands in semiconductors, the valence and conduction bands, and their dependence on various material and external parameters.A set of bands (subbands), created by the splitting and hybridization (see below) of the ground state of valence electrons, taken together are referred to as the valence band. The number of states contained in this band is given by the multiplicity of its atomic state (typically 4 for sp 3 hybridization), multiplied by the number of atoms creating this band, e.g., the number of atoms in an entire ideal crystal. 1The formation of such bands is often shown as it evolves from the spectrum of isolated atoms when they are brought together to form the crystal lattice. Their levels split with decreasing interatomic distance, as shown in Fig. 1 and discussed in Section "1" of chapter "▶ The Origin of Band Structure". There are several possibilities for the energy and electron distribution over these levels, depending on the crystal bonding and structure. Three relatively simple examples are given in Fig. 1. Figure 1a shows the splitting and overlap of the s and p bands of a main-group metal. The atomic states remain nearly unchanged when the atoms approach each other (here s and p bands do not mix) to form a metal.*Email: pohl@physik.tu-berlin.de 1 In a real crystal this number is reduced since electron scattering limits the coherence length of the electron wave (i.e., the length in which quantum-mechanical interaction can take place). With a mean free path l the number of atoms responsible for the band-level splitting is of the order of (l/a) 3 for a primitive cubic lattice with lattice constant a. Each of these levels is broadened by collision broadening; therefore, even for l approaching a, the result is still bands rather than discrete levels.Semiconductor Physics

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Ordered structures in GaAs0.5Sb0.5 alloys grown by organometallic vapor phase epitaxy

Cited by 242 publications

References 14 publications

Surface Stability of Ordered Ga_0.5In_0.5P and GaAs_0.5Sb_0.5Alloys

Surface Stability of Ordered Ga_0.5In_0.5P and GaAs_0.5Sb_0.5Alloys

Optical and electrical characterization of OMVPE-grown AlGaAsSb epitaxial layers on InP substrates

Bands and Bandgaps in Solids

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Ordered structures in GaAs0.5Sb0.5 alloys grown by organometallic vapor phase epitaxy

Cited by 242 publications

References 14 publications

Surface Stability of Ordered Ga0.5In0.5P and GaAs0.5Sb0.5Alloys

Surface Stability of Ordered Ga0.5In0.5P and GaAs0.5Sb0.5Alloys

Optical and electrical characterization of OMVPE-grown AlGaAsSb epitaxial layers on InP substrates

Bands and Bandgaps in Solids

Contact Info

Product

Resources

About

Surface Stability of Ordered Ga_0.5In_0.5P and GaAs_0.5Sb_0.5Alloys

Surface Stability of Ordered Ga_0.5In_0.5P and GaAs_0.5Sb_0.5Alloys