The Study of Interfaces in Gaas

Cho, N.-H.; Rasmussen, Daniel; McKernan, Stuart; Carter, C.B.; Wagner, David K.

doi:10.1557/proc-122-33

Cited by 2 publications

(5 citation statements)

References 11 publications

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“…The asymmetrical nature of the fringe contrast is a function of crystal and beam tilt, and may be convoluted by the presence of microscope aberrations such as three-fold astigmatism . For compounds with a small difference in the scattering factors, such as GaAs, contrast asymmetries attributable to the crys-tal polarity have not been observed experimentally (Zandbergen et al, 1987;Cho et al, 1988;Lee et al, 1990). Furthermore, crystal polarity cannot be inferred from HRTEM lattice fringes in all cubic compound semiconductors.…”

Section: Crystal Polarity Dislocations and Grain Boundariesmentioning

confidence: 99%

“…The polarity across coherent twin boundaries in com- pound semiconductors has been studied by high-resolution transmission electron microscopy (HRTEM) in ZnSe (Shiojiri et al, 1982;Williams and Wright, 1987), GaAs (De Cooman et al, 1985;Zandbergen et al, 1987;Cho et al, 1988), and GaP (Phillipp et al, 1994b). The stacking of {111} planes across coherent twin boundaries can be viewed edge on along the 〈110〉 zone in HRTEM images.…”

Section: Crystal Polarity Dislocations and Grain Boundariesmentioning

confidence: 99%

“…Contrast asymmetries can be detected only for compound semiconductors with a large difference in the atomic scattering factors of the basis atoms such as ZnSe and GaP (Glaisher et al, 1989). For compounds with a small difference in the scattering factors, such as GaAs, contrast asymmetries attributable to the crys-tal polarity have not been observed experimentally (Zandbergen et al, 1987;Cho et al, 1988;Lee et al, 1990).…”

Section: Crystal Polarity Dislocations and Grain Boundariesmentioning

confidence: 99%

“…Polycrystalline semiconductors are promising materials for optoelectronic devices such as photovoltaic cells, thin-film transistors, and ␥-ray detectors. The experimental difficulties determining the crystal polarity in all but a few samples with specialized geometries has limited the extent to which grain boundaries could be studied in compound semiconductors (Cho et al, 1988;Cohen and Carter, 1997). It is established that the physical properties of grain boundaries are related to the structure of such defects (Grovenor, 1985).…”

Section: Introductionmentioning

confidence: 99%

“…While the structure and properties of grain boundaries in semiconductors have been the subject of numerous studies, the influence of crystal polarity on grain-boundary structure has yet to be fully investigated. The experimental difficulties determining the crystal polarity in all but a few samples with specialized geometries has limited the extent to which grain boundaries could be studied in compound semiconductors (Cho et al, 1988;Cohen and Carter, 1997). In this study, the use of convergent-beam electron-diffraction (CBED) techniques to evaluate the nature of polar bonding across ⌺ = 3 co-herent and lateral twin boundaries in gallium phosphide (GaP) is reported.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the Absolute Crystal Polarity across Twin Boundaries in Gallium Phosphide Using Convergent-Beam Electron Diffraction

1999

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: The measurement of absolute crystal polarity is crucial to understanding the structural properties of many planar defects in compound semiconductors. Grain boundaries, including twin boundaries, in the sphalerite lattice are uniquely characterized by the crystallographic misorientation of individual grains and the direction of the crystal polarity in domains adjoining the grain boundary. To evaluate crystal polarity in gallium phosphide (GaP), asymmetrical interference contrast in convergent-beam electron-diffraction (CBED) patterns was used to ascertain the nature and direction of polar bonds. The direction of the asymmetry in the electron diffraction reflections was correlated with the crystal polarity of a sample with known polarity. The CBED technique was applied to determine the polar orientation of grains adjoining Sigma = 3 coherent and lateral twin boundaries in polycrystalline GaP.

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Section: Crystal Polarity Dislocations and Grain Boundariesmentioning

confidence: 99%

Section: Crystal Polarity Dislocations and Grain Boundariesmentioning

confidence: 99%

Section: Crystal Polarity Dislocations and Grain Boundariesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterization of the Absolute Crystal Polarity across Twin Boundaries in Gallium Phosphide Using Convergent-Beam Electron Diffraction

1999

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Theoretical study of polar interfaces of the (122) Sigma =9 grain boundary in cubic SiC

Kohyama¹,

Kose²,

Yamamoto³

1991

J. Phys.: Condens. Matter

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The polar and non-polar interfacesof grain boundariesin the zinc blendestructure canbedefined bythestoichiometryin theinterfaceregion,andit ispossibletoconstruct two polar interfaces and one non-polar interface for a symmetrical-tilt grain boundary for which the interface comprises the polar surfaces. The atomic and electronic structures of polar interfaces of the {122) 2 = 9 grain boundary in S i c have been examined using the selfconsistent tight-binding method coupled with the supercell technique, and they have been comparedwithourpreviousresultsfor thenon-polarinterface. In thepresentatomicmodels consistingofazigzagarrangement of5-7units. whichisconsistent withan ~n ~~i m a g e , o n e polar interlace contains the C--C wrong bonds and another polar interface contains the Si-Si wrong bonds, although the non-polar interface contains both types of wrong bonds. The present calculated results indicate that as well as the non-polar interface the respective polar interfaces are possibly stable without the generation of any macroscopic electrostatic fieldsor excess free carriers, although thewrong bondsintroducelocalizedstatesat the band edges and an increase in the electrostatic energy similar to the non-polar interface. This is because the atomicchargesin SiCare mainlycaused by the bond polarization and the wrong bonds do not generate any extra carriers or deep states in Sic, unlike ionic solids or heterovalent compound semiconductors. The calculated energy of formation of the pair of polar interfaces is rather smaller than that of the non-polar interfaces, because the energy increasecaused by bonddistortionsissmaller in the polarinterfaces.which containonlyone type of wrong bond. By using the calculated binding energies, the relative stability of the polar and non-polar interfaces of the (122) E = 9 boundary in Sic has been analysed thermodynamically as a function of the atomic chemical potentials. The calculated thermodynamic potentials of the interfaces indicate that either one or the other polar interlace is always more stable than the non-polar interface for the allowable ranges of the atomic chemical potentials. There is a general discussion of the stability of the polar interfaces in Sic and in compound semiconductors.

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The Study of Interfaces in Gaas

Cited by 2 publications

References 11 publications

Characterization of the Absolute Crystal Polarity across Twin Boundaries in Gallium Phosphide Using Convergent-Beam Electron Diffraction

Characterization of the Absolute Crystal Polarity across Twin Boundaries in Gallium Phosphide Using Convergent-Beam Electron Diffraction

Theoretical study of polar interfaces of the (122) Sigma =9 grain boundary in cubic SiC

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