Optical properties of the deep Mn acceptor in GaN:Mn

Korotkov, R. Y.; Gregie, J. M.; Wessels, Bruce W.

doi:10.1063/1.1456544

Cited by 169 publications

(119 citation statements)

References 17 publications

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“…However, an essential ingredient of this model is a p-type carrier concentration of around 10 20 cm -3 , a value significantly higher than the highest hole concentrations so far obtained in GaN. Furthermore, optical measurements have indicated that the Mn acceptor level lies over 1eV above the valence band maximum in Wurtzite (Ga,Mn)N [9,10], which is in agreement with density-of-states calculations [11]. Therefore, in contrast to the case for (Ga,Mn)As, Mn does not appear to be an efficient acceptor in Wurtzite GaN, and may not be expected to interact strongly with delocalised charge carriers in the conduction or valence bands.…”

Section: Introductionmentioning

confidence: 99%

p -type conductivity in cubic (Ga,Mn)N thin films

Edmonds

Novikov

Sawicki

et al. 2005

Applied Physics Letters

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The electrical and magnetic properties of p-type cubic (Ga,Mn) IntroductionThe emerging field of semiconductor spintronics relies on the ability to manipulate the electron spin in a semiconductor device, thus offering new prospects for non-volatile high speed information storage and processing. An important milestone in this field was the discovery of carrier-mediated ferromagnetism in III-V compounds doped with Mn [1]. Intensive efforts have since led to ferromagnetic transition temperatures T C in excess of 150K in (Ga,Mn)As [2,3,4], and an impressive range of prototype devices [5,6,7]. However, for widespread technological usage of these systems, a T C significantly above 300K is necessary, which may yet require the development of new materials.In this context, the Zener mean-field model prediction of room temperature ferromagnetism in (Ga,Mn) , a value significantly higher than the highest hole concentrations so far obtained in GaN. Furthermore, optical measurements have indicated that the Mn acceptor level lies over 1eV above the valence band maximum in Wurtzite (Ga,Mn)N [9,10], which is in agreement with density-of-states calculations [11]. Therefore, in contrast to the case for (Ga,Mn)As, Mn does not appear to be an efficient acceptor in Wurtzite GaN, and may not be expected to interact strongly with delocalised charge carriers in the conduction or valence bands. In spite of this, there are numerous observations of room temperature ferromagnetism in n-type (Ga,Mn)N, even in cases where no secondary phases have been identified [12]. The origin of the ferromagnetism in these cases is unresolved, but no conclusive evidence for a coupling between magnetic and semiconductor properties has been demonstrated, and it appears that this effect lies outside the Zener model prediction.It may be expected that Mn incorporation is favoured in the metastable zincblende (cubic) phase of GaN, since MnN is itself cubic with a similar lattice constant to GaN. at room temperature [14]. Cubic (Ga,Mn)N may therefore be a more promising candidate than the Wurtzite phase for room temperature carrier-mediated ferromagnetism. It is important to determine the origin of the p-type conductivity and investigate the nature of the Mn state in this material. Here we report on a detailed study of the electrical and magnetic properties of cubic (Ga,Mn)N films grown on GaAs(001) by molecular beam epitaxy. Growth and structureUndoped cubic GaN films and cubic (Ga,Mn)N layers were grown on semi-insulating GaAs (001) substrates by plasma-assisted molecular beam epitaxy (PA-MBE) using arsenic as a surfactant to initiate the growth of cubic phase material [15]. Films where grown under Nrich conditions, which has been found to be necessary for the effective substitutional incorporation of Mn in hexagonal (Ga,Mn)N [16]. The substrate temperature was measured using an optical pyrometer. Growth temperatures from 450 to 680 o C were used. The active nitrogen for the growth of the group III-nitrides was provided by an CARS25 RF activated plasma source...

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Section: Introductionmentioning

confidence: 99%

p -type conductivity in cubic (Ga,Mn)N thin films

Edmonds

Novikov

Sawicki

et al. 2005

Applied Physics Letters

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“…In the optical characterization of ͑Ga,Mn͒N, photoluminescence ͑PL͒ peaks were observed at 2.5 and 3.0 eV in Mn-implanted and annealed GaN. 11 The Mn impurities in GaN, acting as a deep acceptor for electrons at an energy level of E v ϩ1.4 eV, played a role in strongly disordering the lattice structure. 12 Despite a number of works mentioned above, no experimental evidence on the effects of such secondary phases and lattice imperfections on both the ferromagnetic and optical properties in GaN-based DMS was provided because of lack of experimental resolution.…”

Section: Introductionmentioning

confidence: 99%

Microstructural, optical, and magnetic properties of Mn-implanted p-type GaN

Baik

Lee

Shon

et al. 2003

Journal of Applied Physics

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The effect of microstructural change on both magnetic and optical properties of Mn-implanted p-type GaN was studied. A dilute magnetic semiconductor was achieved by implanting Mn ions into p-type GaN and subsequently annealing. The magnetization measurement showed that the Curie temperature was the highest in the 800°C annealed sample due to the formation of Ga-Mn magnetic phases. The annealing at a higher temperature of 900°C produced antiferromagnetic Mn-N compounds such as Mn 6 N 2.58 and Mn 3 N 2 , leaving N vacancies. This provides evidence that N vacancies played a critical role in weakening the ferromagnetic property in the Mn-implanted GaN. The photoluminescence peak at 2.92 eV became strong after annealing at 800°C, indicating an increase in hole concentration due to an enhanced activation of Mn impurities in p-type GaN. The intensity of Raman modes at 290 and 670 cm Ϫ1 decreased drastically as annealing temperature increased ͑Ͼ800°C͒, due to the reduction in Mn-implantation-induced lattice imperfections. From this, it is proposed that the increase in magnetic properties of Mn-implanted GaN originated from the enhancement in the crystallinity as well as the production of Ga-Mn magnetic phases.

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“…Early experimental [34][35][36] and density functional theory (DFT) studies [37][38][39][40][41][42] demonstrated a partially filled impurity band formed deeply in the band gap with a significant Mn d character, suggesting a Mn 3+ (d 4 ) configuration different from the Mn 2+ (d 5 ) one in Ga 1−x Mn x As [43]. Later, both x-ray absorption spectroscopy (XAS) studies [44][45][46] and optical absorption analysis [47,48] also concluded a Mn valence state of 3+ (d 4 ).…”

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confidence: 99%

What is the Valence of Mn inGa1−xMnxN?

et al. 2015

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We investigate the current debate on the Mn valence in Ga1−xMnxN, a diluted magnetic semiconductor (DMSs) with a potentially high Curie temperature. From a first-principles Wannier-function analysis, we unambiguously find the Mn valence to be close to 2+ (d 5 ), but in a mixed spin configuration with average magnetic moments of 4µB. By integrating out high-energy degrees of freedom differently, we further derive for the first time from first-principles two low-energy pictures that reflect the intrinsic dual nature of the doped holes in the DMS: 1) an effective d 4 picture ideal for local physics, and 2) an effective d 5 picture suitable for extended properties. In the latter, our results further reveal a few novel physical effects, and pave the way for future realistic studies of magnetism. Our study not only resolves one of the outstanding key controversies of the field, but also exemplifies the general need for multiple effective descriptions to account for the rich low-energy physics in many-body systems in general.

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Optical properties of the deep Mn acceptor in GaN:Mn

Abstract: Articles you may be interested inDeep level transient spectroscopy in plasma-assisted molecular beam epitaxy grown Al 0.2 Ga 0.8 N / GaN interface and the rapid thermal annealing effect

Cited by 169 publications

References 17 publications

p -type conductivity in cubic (Ga,Mn)N thin films

p -type conductivity in cubic (Ga,Mn)N thin films

Microstructural, optical, and magnetic properties of Mn-implanted p-type GaN

What is the Valence of Mn inGa1−xMnxN?

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