Green luminescence in Mg-doped GaN

Reshchikov, M. A.; Demchenko, D. O.; McNamara, J. D.; Fernández-Garrido, Sergio; Calarco, Raffaella

doi:10.1103/physrevb.90.035207

Cited by 143 publications

(162 citation statements)

References 45 publications

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“…[16] for a more detailed discussion of several arguments that support this theory from the viewpoint of electrical and optical characterization methods. Low formation energies for interstitial Mg i if the Fermi level is located below mid gap were also theoretically predicted by Reshchikov et al [17].…”

supporting

confidence: 69%

“…However, while "GaN:Mg" samples were used as-grown, "p-GaN:Mg" samples were annealed for 20 min at 800°C under nitrogen atmosphere in order to drive out H and electrically activate the Mg [24]. While no electrical characterization was performed for the p-GaN:Mg used in this experiment, typical hole concentrations and Hall mobilities for samples produced using the same equipment under almost identical conditions are 1-2×10 17 cm −3 and 10-15 cm 2 /Vs [25]. The EC measurements were performed simultaneously with 50 keV implantations into a 1 mm diameter beam spot using the on-line setup described in Ref.…”

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confidence: 99%

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Lattice Location of Mg in GaN: A Fresh Look at Doping Limitations

et al. 2017

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Radioactive27 Mg (t 1/2 =9.5 min) was implanted into GaN of different doping types at CERN's ISOLDE facility and its lattice site determined via β − emission channeling. Following implantations between room temperature and 800°C, the majority of 27 Mg occupies the substitutional Ga sites, however, below 350°C significant fractions were also found on interstitial positions ~0.6 Å from ideal octahedral sites. The interstitial fraction of Mg was correlated with the GaN doping character, being highest (up to 31%) in samples doped p-type with 2×1019 cm −3 stable Mg during epilayer growth, and lowest in Si-doped n-GaN, thus giving direct evidence for the amphoteric character of Mg. Implanting above 350°C converts interstitial 27 Mg to substitutional Ga sites, which allows estimating the activation energy for migration of interstitial Mg as between 1.3 and 2.0 eV.

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confidence: 99%

Lattice Location of Mg in GaN: A Fresh Look at Doping Limitations

et al. 2017

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“…The shape of the YL band I PL ( ω) and position of its maximum ω max remained unchanged for excitation intensities up to 0.2 W/cm 2 . The shape of the YL band at low temperature can be modeled with the following formula derived from a one-dimensional configuration coordinate model [23] …”

Section: A Yellow and Blue Luminescence Bands In Gan Grown By Mocvdmentioning

confidence: 99%

Carbon defects as sources of the green and yellow luminescence bands in undoped GaN

et al. 2014

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In high-purity GaN grown by hydride vapor phase epitaxy, the commonly observed yellow luminescence (YL) band gives way to a green luminescence (GL) band at high excitation intensity. We propose that the GL band with a maximum at 2.4 eV is caused by transitions of electrons from the conduction band to the 0/+ level of the isolated C N defect. The YL band, related to transitions via the −/0 level of the same defect, has a maximum at 2.1 eV and can be observed only for some high-purity samples. However, in less pure GaN samples, where no GL band is observed, another YL band with a maximum at 2.2 eV dominates the photoluminescence spectrum. The latter is attributed to the C N O N complex.

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“…Results similar to the HSE calculations were found in other studies employing hybrid functionals. 77,78 However, V 0 N was not found to be stable in ref. 78, and the (0/−) transition level was found to occur 4 meV below the CBM in ref.…”

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confidence: 95%

“…76 A similar optical transition was calculated in ref. 77. This transition would explain the occurrence of yellow luminescence in p-type GaN, 81,82 in which nitrogen vacancies are expected to occur as compensating centers due to their low formation energies.…”

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confidence: 99%

Computationally predicted energies and properties of defects in GaN

2017

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Recent developments in theoretical techniques have significantly improved the predictive power of density-functional-based calculations. In this review, we discuss how such advancements have enabled improved understanding of native point defects in GaN. We review the methodologies for the calculation of point defects, and discuss how techniques for overcoming the band-gap problem of density functional theory affect native defect calculations. In particular, we examine to what extent calculations performed with semilocal functionals (such as the generalized gradient approximation), combined with correction schemes, can produce accurate results. The properties of vacancy, interstitial, and antisite defects in GaN are described, as well as their interaction with common impurities. We also connect the first-principles results to experimental observations, and discuss how native defects and their complexes impact the performance of nitride devices. Overall, we find that lower-cost functionals, such as the generalized gradient approximation, combined with band-edge correction schemes can produce results that are qualitatively correct. However, important physics may be missed in some important cases, particularly for optical transitions and when carrier localization occurs.

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Green luminescence in Mg-doped GaN

Cited by 143 publications

References 45 publications

Lattice Location of Mg in GaN: A Fresh Look at Doping Limitations

Lattice Location of Mg in GaN: A Fresh Look at Doping Limitations

Carbon defects as sources of the green and yellow luminescence bands in undoped GaN

Computationally predicted energies and properties of defects in GaN

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