Local vibrational modes as a probe of activation process in <i>p</i>-type GaN

Harima, Hiroshi; Inoue, Taeko; Nakashima, S.; Ishida, Masaya; Taneya, M.

doi:10.1063/1.124701

Cited by 63 publications

(57 citation statements)

References 16 publications

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“…However, this LVM is usually not visible in as-grown GaN:Mg, due to the fact that the formation of a Mg-N-H complex significantly distorts the Mg Ga -N 4 tetrahedron. 10,26 In our case, the presence of this peak in as-grown samples can be explained taking into account the atomic arrangement of Mg and Mn in GaN. As shown by SIMS measurements, 5 the presence of Mn in (Ga,Mn)N:Mg induces the H concentration to be between one and two orders of magnitude lower than in GaN:Mg.…”

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confidence: 84%

“…[9][10][11]15 In the studied energy range, only the local vibrational mode (LVM) at 657 cm À1 for substitutional Mg in GaN is expected. However, as-grown samples generally do not exhibit this mode, since H is bound to Mg in Mg-N-H complexes, which are Raman-silent in this range.…”

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confidence: 99%

“…Raman spectroscopy is particularly suitable to investigate impurities and impurity complexes in semiconductors 6 due to its sensitivity to variations in the structural and electronic properties of the material under study. In the case of doping of nitrides with Mg, this technique was decisive to identify the Mg-H complexes 7,8 responsible for the low efficiency of the Mg activation, and for the consequent poor p-type conductivity especially in GaN:Mg. [9][10][11] While Mg is the most relevant p-type dopant in GaN, and is employed in the majority of optoelectronic devices based on GaN, Mn generated interest lately for its potential in spintronics, and particularly in the perspective of turning p-type Mn-doped GaN (i.e., (Ga,Mn)N:Mg) into a ferromagnetic dilute magnetic semiconductor with a high Curie transition temperature. 12 Moreover, the recent demonstration of unexpected (infrared) optical and magnetic responses in (Ga,Mn)N:Mg, 5 has opened appealing fundamental and technological perspectives for this system.…”

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confidence: 99%

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Functional Mn–Mgk cation complexes in GaN featured by Raman spectroscopy

Devillers

Leite

Silva

et al. 2013

Applied Physics Letters

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The evolution of the optical branch in the Raman spectra of (Ga,Mn)N:Mg epitaxial layers as a function of the Mn and Mg concentrations, reveals the interplay between the two dopants. We demonstrate that the various Mn-Mg-induced vibrational modes can be understood in the picture of functional Mn–Mgk complexes formed when substitutional Mn cations are bound to k substitutional Mg through nitrogen atoms, the number of ligands k being driven by the ratio between the Mg and the Mn concentrations.

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confidence: 84%

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Functional Mn–Mgk cation complexes in GaN featured by Raman spectroscopy

Devillers

Leite

Silva

et al. 2013

Applied Physics Letters

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“…[43][44][45][46] It is quite possible that the same technique would also be able to observe the modes for Be Ga as they are so similar. These defects also have bands of nearly degenerate E modes slightly below each of the A 1 TABLE I.…”

Section: A Be Ga Acceptormentioning

confidence: 99%

Calculated properties of point defects in Be-doped GaN

et al. 2003

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The properties of several point defects in hexagonal gallium nitride that can compensate beryllium shallow acceptors (Be Ga ) are calculated using the AIMPRO method based on local density functional theory. Be Ga itself is predicted to have local vibrational modes ͑LVM's͒ very similar to magnesium acceptors. The highest frequency is about 663 cm Ϫ1 . Consistent with other recent studies, we find that interstitial beryllium double donors and single-donor beryllium split interstitial pairs at gallium sites are very likely causes of compensation. The calculations predict that the split interstitial pairs possess three main LVM's at about 1041, 789, and 738 cm Ϫ1 . Of these, the highest is very close to the experimental observation in Be-doped GaN. Although an oxygen donor at the nearest-neighboring site to a beryllium acceptor (Be Ga -O N ) is also a prime suspect among defects that are possibly responsible for compensation, its highest frequency is calculated to be about 699 cm Ϫ1 and hence is not related in any way to the observed center. Another mode for this defect is estimated to be about 523 cm Ϫ1 and is localized on the O N atom. These two vibrations of Be Ga -O N are thus equivalent to those for the isolated substitutional centers perturbed by the presence of their impurity partners.

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“…The frequencies of the LVMs of both Be Ga and Mg Ga are below the A 1 ͑LO, 735 cm Ϫ1 ) phonon frequency of GaN, yet are in bands where the bulk phonon density of states are low, thus allowing the modes for Mg Ga defects in GaN to be observed by Raman experiments scattering. [2][3][4][5] . It is quite likely, therefore, that the modes for Be Ga defects could also be detected by the same technique.…”

Section: Introductionmentioning

confidence: 99%

Calculated properties of nitrogen-vacancy complexes in beryllium- and magnesium-doped GaN

et al. 2003

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The properties of defect complexes consisting of a nitrogen vacancy with a substitutional beryllium or magnesium atom on neighboring lattice sites in hexagonal GaN are calculated using the AIMPRO local-densityfunctional theory method. Both types of defects V N -Be Ga and V N -Mg Ga are bound with respect to their isolated constituents. They do not appear to have any electronic levels in the bandgap, and are expected to be neutral defects. Important structural differences are found. In its minimum energy configuration, the Be atom in the V N -Be Ga complex lies nearly in the same plane as the three equivalent N atoms nearest to it. Thus, it has shorter Be-N bonds than the Ga-N distance in the bulk crystal, while the Mg atom in the V N -Mg Ga complex occupies a position closer the lattice site of the Ga atom it replaces. Hence, the V N -Be Ga complex has a larger open volume than the V N -Mg Ga complex. This is consistent with positron annihilation experiments ͓Saarinen et al., J. Cryst. Growth 246, 281 ͑2002͒; Hautakangas et al., Phys. Rev. Lett. 90, 137402 ͑2003͔͒. The frequency of the highest local vibrational mode of the V N -Be Ga center is calculated to be within 3-4 % of an infrared absorption line detected in Be-doped GaN ͓Clerjaud ͑private communication͔͒.

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Local vibrational modes as a probe of activation process in p-type GaN

Cited by 63 publications

References 16 publications

Functional Mn–Mgk cation complexes in GaN featured by Raman spectroscopy

Functional Mn–Mgk cation complexes in GaN featured by Raman spectroscopy

Calculated properties of point defects in Be-doped GaN

Calculated properties of nitrogen-vacancy complexes in beryllium- and magnesium-doped GaN

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