Charactrization of Residual Transition Metal Ions in GaN and AIN

Baur, John P.; Kaufmann, U.; Kunzer, M.; Schneider, J.; Amano, Hiroshi; Akasaki, Isamu; Detchprohm, Theeradetch; Hiramatsu, Kazumasa

doi:10.4028/www.scientific.net/msf.196-201.55

Cited by 17 publications

(6 citation statements)

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“…One might notice that according to the result of the mHSE calculation there is no double positive charge state, because in the positive charge state of Cr Al all of the occupied defect states fall into the valence band. On the other hand there are experimental indications 78,79 and theoretical predictions 80 of the existence of Cr 5+ in w-AlN. This contradiction may indicate the inaccuracy of the mHSE functional and the necessity of the correction.…”

Section: B Cr Al In W-alnmentioning

confidence: 96%

Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

et al. 2014

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Hybrid functionals serve as a powerful practical tool in different fields of computational physics and quantum chemistry. On the other hand, their applicability for the case of correlated d and f orbitals is still questionable and needs more considerations. In this article we formulate the on-site occupation dependent exchange correlation energy and effective potential of hybrid functionals for localized states and connect them to the on-site correction term of the DFT + U method. The resultant formula indicates that the screening of the onsite electron repulsion is governed by the ratio of the exact exchange in hybrid functionals. Our derivation provides a theoretical justification for adding a DFT + U -like on-site potential in hybrid-DFT calculations to resolve issues caused by overscreening of localized states. The resulting scheme, hybrid DFT + V w , is tested for chromium impurity in wurtzite AlN and vanadium impurity in 4H-SiC, which are paradigm examples of systems with different degrees of localization between host and impurity orbitals.

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Section: B Cr Al In W-alnmentioning

confidence: 96%

Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

et al. 2014

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“…Based on a comparison with the position of the Mn 2+ acceptor level (with respect to the vacuum energy) in GaAs, GaP and InP, the Mn 2+ level in GaN is expected at 2.0 ± 0.1 eV above the valence band [10]. Therefore, the ansorption peak is more likely related to the neutral Mn 3+ acceptor state.…”

Section: Discussionmentioning

confidence: 99%

Optical Properties of Mn-doped GaN

et al. 2003

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Molecular beam epitaxy-grown GaN with different Mn concentrations (5-23 x 1019 cm -3 ) and codoped with Si were investigated by cathodoluminescence (CL) spectroscopy and optical transmission measurements. In the GaN:Mn, an intense absorption peak at 1.414 +/-0.002 eV was observed. This peak was attributed to an internal 5 T 2 5 E transition of the deep neutral Mn 3+ state since its intensity scaled with the Mn 3+ concentration. The CL measurements showed that Mn-doping concentrations around 10 20 cm -3 had three effects on the emission spectrum: (i) the donor bound exciton at 3.460 eV was reduced by more than one order of magnitude, (ii) the donor-acceptor-pair band at 3.27 eV was completely quenched and (iii) the yellow luminescence centered at 2.2 eV was the strongly decreased. The latter two effects were attributed to a reduced concentration of V Ga . In the infrared spectral range, three broad, Mn-doping related CL emission bands centered at 1.01 ± 0.02 eV, 1.09 ± 0.02 eV and 1.25 ± 0.03 eV were observed. These bands might be related to deep donor complexes, which are generated as a result of the heavy Mn-doping, rather than internal transitions at the Mn atom.

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“…GaN is considered to be one of the most promising semiconductor materials for the construction of short-wavelength emitting devices, such as blue diodes and lasers [1]. Since transition-metal impurities in semiconductors are known to be a practically unavoidable contamination and the presence of these impurities can influence the semiconductors characteristics and device performance, the identification and study of these impurities in GaN by using spectroscopy methods have attracted research interest [2][3][4][5][6][7]. A zero-phonon line (ZPL) at 1.193 eV in GaN was found using the optical spectrum measurements [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…Since transition-metal impurities in semiconductors are known to be a practically unavoidable contamination and the presence of these impurities can influence the semiconductors characteristics and device performance, the identification and study of these impurities in GaN by using spectroscopy methods have attracted research interest [2][3][4][5][6][7]. A zero-phonon line (ZPL) at 1.193 eV in GaN was found using the optical spectrum measurements [3][4][5][6]. The identification of this ZPL with a 1 E → 3 A 2 transition of a 3d 2 configuration is beyond question [5,7].…”

Section: Introductionmentioning

confidence: 99%

“…The identification of this ZPL with a 1 E → 3 A 2 transition of a 3d 2 configuration is beyond question [5,7]. However, the assignment to Cr 4+ [3,4] or Ti 2+ [5,6] impurities (note: in this paper, the ionic notation formulated by Clerjaud [8] is used to designate the electronic arrangement of the transition-metal impurity in GaN) is discussed controversially.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical studies of theg-shift for Cr⁴⁺ions in GaN crystal from crystal-field and charge-transfer mechanisms

Zheng¹,

Wu²,

Zijian³

2001

J. Phys.: Condens. Matter

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The assignment of the 1.193 eV zero-phonon line of the 3d2 ion in GaN crystal to the internal luminescence of Cr4+ on the Ga3+ site is analysed. Based on this assignment, the g-shift Δg ( = g-gs) of the groundstate of this luminescence is calculated by considering not only the conventional contribution due to the crystal-field mechanism, but also the contribution due to charge-transfer mechanism. The calculated result shows good agreement with the observed value, suggesting that the assignment is reasonable. The calculated Δg due to the charge-transfer mechanism is opposite in sign and 62% in magnitude, compared with that due to the crystal-field mechanism, and so it cannot be neglected. It appears that for the 3d2 (or 3dn) ion with a high valence state in crystals (particularly, in the case of the ligand having small optical electronegativity), the reasonable explanation of the g-shift should consider the contributions from both the crystal-field and charge-transfer mechanisms.

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Charactrization of Residual Transition Metal Ions in GaN and AIN

Cited by 17 publications

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Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

Optical Properties of Mn-doped GaN

Theoretical studies of theg-shift for Cr⁴⁺ions in GaN crystal from crystal-field and charge-transfer mechanisms

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Charactrization of Residual Transition Metal Ions in GaN and AIN

Cited by 17 publications

References 0 publications

Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

Optical Properties of Mn-doped GaN

Theoretical studies of theg-shift for Cr4+ions in GaN crystal from crystal-field and charge-transfer mechanisms

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Theoretical studies of theg-shift for Cr⁴⁺ions in GaN crystal from crystal-field and charge-transfer mechanisms