Mechanism of self-diffusion in diamond

Bernholc, J.; Antonelli, Alex; Sole, T. M. Del; Bar‐Yam, Yaneer; Pantelides, S. T.

doi:10.1103/physrevlett.61.2689

Cited by 166 publications

(65 citation statements)

References 26 publications

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“…Likewise, the current views of the Jahn-Teller effect are very close to those of Lannoo and Stoneham [7] expressed in 1968. However, there has been very little theory of the relative energies involved in changing the charge state, so there is significant confusion about photoionization energies, though some guidance can be had from the work of Bernholc et al [8]. Questions like 'where is the vacancy ground state in the gap?'…”

Section: Introductionmentioning

confidence: 99%

Stability of electronic states of the vacancy in diamond

Mainwood

Stoneham

1997

J. Phys.: Condens. Matter

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Abstract. The vacancy in diamond is a fundamental defect which has been studied theoretically and experimentally for forty years. However, although early theories (Coulson C A and Kearsley M J 1957 Proc. R. Soc. A 241 433) were extremely successful in explaining the nature of the ground state of the neutral defect and the Jahn-Teller distortion expected Stoneham A M 1968 J. Phys. Chem. Solids 29 1987), there are still several questions which have not been answered satisfactorily. In particular, the many-electron effects and configuration interaction are vital. They determine not only the order of electronic levels in the vacancy, but also the best-known optical transition, GR1, which cannot be expressed in terms of one-electron levels alone.We bring together much of the detailed recent experimental data on the different charge states and excited states of the vacancy to build up a simple empirical model of the defect. We show that the stability of the states and their photoconductivity, or lack of it, can be reproduced. We can predict that other states of the neutral vacancy, observable by EPR, lie very close above the ground state, and another high-energy optical transition might be detectable.

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Section: Introductionmentioning

confidence: 99%

Stability of electronic states of the vacancy in diamond

Mainwood

Stoneham

1997

J. Phys.: Condens. Matter

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“…[10][11][12][13] In addition, the kinetic properties of defects, such as diffusion mechanisms and migration energies, strongly depend on the charge state. [14][15][16] Moreover, chemical reactions involving bond formation and dissociation can also be explained in terms of the formation energy, provided it can be calculated with sufficient accuracy. 16,17 Systematic formation energy calculations have been performed for several semiconductors, including Si, [18][19][20] SiC, 21,38 GaN, 22 and diamond.…”

Section: Introductionmentioning

confidence: 99%

“…16,17 Systematic formation energy calculations have been performed for several semiconductors, including Si, [18][19][20] SiC, 21,38 GaN, 22 and diamond. 14,[23][24][25] The formation energy E f of a defect with charge q is given by…”

Section: Introductionmentioning

confidence: 99%

Density-functional calculations of defect formation energies using supercell methods: Defects in diamond

et al. 2005

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Density-functional theory combined with periodic boundary conditions is used to systematically study the dependence of defect formation energy on supercell size for diamond containing vacancy and self-interstitial defects. We investigate the effect of the electrostatic energy due to the neutralization of charged supercells and the effect of the alignment of the valence band maximum ͑VBM͒ on the formation energy. For negatively charged vacancies and positively charged interstitials, the formation energies show a clear dependence on supercell size, and the electrostatic corrections agree with the trend given by the Makov-Payne scheme ͑Ref. 28͒. For positively charged vacancies and negatively charged interstitials, the size dependence and the electrostatic corrections are quite weak. An analysis of the spatial charge density distributions reveals that these large variations in electrostatic terms with defect type originate from differences in the screening of the defect-localized charge, as explained by using a simple electron-gas model. Several VBM alignment schemes are also tested. The best agreement between the calculated and asymptotically exact ionization levels is obtained when the levels are based on the formation energies referenced to the VBM of the defect-containing supercell.

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“…Bernholc et al [30] have indicated that carbon selfdiffusion and vacancy-assisted impurity diffusion in diamond are Fermi level dependent and can be enhanced by dopants because of the lowering of the activation barrier for charged vacancy diffusion. At the diamond growth temperatures (700 900°C), such an enhanced diffusion with boron incorporation could lead to a higher surface mobility and improved incorporation of the carbon atoms at the growing surface into their proper lattice positions, thereby minimizing the formation of structural defects in the films.…”

Section: Line and Planar Defect Density Decreasementioning

confidence: 99%

Effects of boron doping on the surface morphology and structural imperfections of diamond films

Wang

Zhu

et al. 1992

Diamond and Related Materials

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This paper reports the surface morphology and structural imperfection of boron-doped diamond films prepared by microwave plasma enhanced chemical vapor deposition. It was found that boron dopants improved the structural quality of diamond films. The surface morphology consisted mainly of the { 111 } facets. A significant enhancement of nucleation density and consequent decrease of grain size was observed with the addition of diborane in the gas phase. Raman spectroscopy indicated that, with the introduction of boron dopants, the integrated intensity of the diamond peak at 1332 cm-~ increased relative to the intensity of the non-diamond peak at about 1500 cm-1, and the full-width at half maximum of the 1332 cm i peak decreased. In addition, the 1.681 eV (738 nm) photoluminescence peak related to point defects was effectively reduced, or even eliminated by the boron dopants. Finally, transmission electron microscopy studies found that the densities of planar defects (mainly stacking faults and microtwins) also decreased with the boron addition.

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Mechanism of self-diffusion in diamond

Cited by 166 publications

References 26 publications

Stability of electronic states of the vacancy in diamond

Stability of electronic states of the vacancy in diamond

Density-functional calculations of defect formation energies using supercell methods: Defects in diamond

Effects of boron doping on the surface morphology and structural imperfections of diamond films

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