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

Wahl, Ulrich; Amorim, lmarina Pinto de Almeida; Augustyns, V.; Costa, A. R. G.; David-Bosne, E.; Lima, Tiago de Lemos; Lippertz, Gertjan; Correia, J. G.; Silva, da; Kappers, M. J.; Temst, Kristiaan; Vantomme, André; Pereira, L. M. C.

doi:10.1103/physrevlett.118.095501

Cited by 40 publications

(46 citation statements)

References 46 publications

(53 reference statements)

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“…The energy barriers generally increase with ionic radius and ionic charge, but their interplay leads to nontrivial effects. The energy barriers of Mg 2+ calculated in this work support experimental estimates of about 2 eV .…”

Section: Discussionsupporting

confidence: 84%

“…The diffusion is generally quite isotropic, except for Be 2+ , which diffuses with particularly low barriers in directions perpendicular to the c‐axis. The average energy barrier calculated for Mg 2+ is 2.1 eV, in agreement with the range of values estimated in a recent experimental study .…”

Section: Introductionsupporting

confidence: 89%

“…A recent theoretical study has suggested the Mg interstitial (Mg i ) to play a key role in this process . This proposal has subsequently received support from a

β^{-}

emission channeling experiment, which provided a direct proof of the occurrence of Mg i . To complete this picture, it is important to understand the diffusion properties of the Mg interstitial, which determine the device processing procedures and the electrical properties of the grown samples .…”

Section: Introductionmentioning

confidence: 99%

“…The description of the Mg diffusion process in GaN achieved so far is highly inconsistent. Experimental investigations lead to a large spread of diffusion barriers ranging from 1.3 to 5 eV . Recent experimental estimates situate the transition barrier in a fairly large interval ranging from 1.3 to 2.0 eV .…”

Section: Introductionmentioning

confidence: 99%

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Migration of Mg and other interstitial metal dopants in GaN

Miceli

Pasquarello

2017

Physica Rapid Research Ltrs

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The minimum energy paths for the migration of interstitial Mg in wurtzite GaN are studied through density functional calculations. The study also comprises Li, Na, and Be dopants to examine the dependence on size and charge of the dopant species. In all cases considered, the impurities diffuse like ions without any tendency of localizing charge. Li, Mg, and to some extent Na, diffuse almost isotropically in GaN, with average diffusion barriers of 1.1, 2.1, and 2.5 eV, respectively. Instead Be shows a marked anisotropy with energy barriers of 0.76 and 1.88 eV for diffusion paths perpendicular and parallel to the c-axis. The diffusion barrier generally increases with ionic charge and ionic radius, but their interplay is not trivial. The calculated migration barrier for Mg is consistent with the values estimated in a recent beta- emission channeling experiment

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Section: Discussionsupporting

confidence: 84%

Section: Introductionsupporting

confidence: 89%

“…A recent theoretical study has suggested the Mg interstitial (Mg i ) to play a key role in this process . This proposal has subsequently received support from a

β^{-}

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Migration of Mg and other interstitial metal dopants in GaN

Miceli

Pasquarello

2017

Physica Rapid Research Ltrs

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“…Also, some issues related to the accuracy in calculations of Buckeridge et al15 have been reported by other groups41,42 . Recently, Wahl et al43 studied the site occupancy of Mg in GaN by implanting radioactive Mg in GaN, and found a notable amount of Mg in interstitial sites, while the majority of them occupy the substitutional Ga sites. As mentioned earlier, some reports35,36 suggest the formation energy of Mg occupying at interstitial site is less in p-type GaN.…”

mentioning

confidence: 99%

Origin of Blue Luminescence in Mg -Doped GaN

et al. 2019

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We uncover the origin of blue luminescence (BL) peak in Mg doped GaN thin film using a combination of experimental X-ray absorption near edge spectroscopy (XANES), first-principles calculations based on density functional theory and full multiple scattering theoretical analysis of various possible defect complexes and their XANES signatures. We demonstrate that a defect complex composed of Mg substituted at Ga site (Mg Ga ) and Mg at interstitial site (Mg i ) is primarily responsible for the observed BL by Donor-Acceptor Pair transition (DAP) associated with a deep donor state in the gap. It correlates with a higher (lower) oxidation state of N (Ga) in heavily Mg doped GaN than in its pristine structure, evident in our experiments as well as calculations. Physical and chemical mechanisms identified here point out a route to achieving efficient p-type GaN.

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Lattice Location Studies of the Amphoteric Nature of Implanted Mg in GaN

Wahl

Correia

Costa

et al. 2021

Adv Elect Materials

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Despite the renewed interest in ion implantation doping of GaN, efficient electrical activation remains a challenge. The lattice location of 27Mg is investigated in GaN of different doping types as a function of implantation temperature and fluence at CERN's ISOLDE facility. The amphoteric nature of Mg is elucidated, i.e., the concurrent occupation of substitutional Ga and interstitial sites: following room temperature ultra‐low fluence (≈2 × 1010 cm−2) implantation, the interstitial fraction of Mg is highest (20–24%) in GaN pre‐doped with stable Mg during growth, and lowest (2–6%) in n‐GaN:Si, while undoped GaN shows an intermediate interstitial fraction of 10–12%. Both for p‐ and n‐GaN prolonged implantations cause interstitial 27Mg to approach the levels found for undoped GaN. Implanting above 400 °C progressively converts interstitial Mg to substitutional Ga sites due to the onset of Mg interstitial migration (estimated activation energy 1.5–2.3 eV) and combination with Ga vacancies. In all sample types, implantations above a fluence of 1014 cm−2 result in >95% substitutional Mg. Ion implantation is hence a very efficient method to introduce Mg into substitutional Ga sites, i.e., challenges toward high electrical activation of implanted Mg are not related to lack of substitutional incorporation.

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

Cited by 40 publications

References 46 publications

Migration of Mg and other interstitial metal dopants in GaN

Migration of Mg and other interstitial metal dopants in GaN

Origin of Blue Luminescence in Mg -Doped GaN

Lattice Location Studies of the Amphoteric Nature of Implanted Mg in GaN

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