Magnesium diffusion profile in GaN grown by MOVPE

Benzarti, Z.; Halidou, I.; Bougrioua, Z.; Boufaden, T.; Jani, B. El

doi:10.1016/j.jcrysgro.2008.04.008

Cited by 38 publications

(23 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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%

See 1 more Smart Citation

Migration of Mg and other interstitial metal dopants in GaN

Miceli

Pasquarello

2017

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

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

show abstract

Section: Discussionsupporting

confidence: 84%

“…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%

Migration of Mg and other interstitial metal dopants in GaN

Miceli

Pasquarello

2017

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

show abstract

“…This could be particularly critical at the growth temperature of 1300 K. An experimental study has determined the diffusion coefficient of Mg in GaN to follow an Arrhenius behavior, characterized by an acrtivation energy of 1.9 eV and a prefactor of D 0 = 2.8 × 10 −7 cm 2 /s. 51 On this basis, we estimate a linear diffusion length of 0.13 µm for a period of two hours, corresponding to typical growth conditions. This distance is short compared to typical layer thicknesses of 1 to 2 µm.…”

Section: A Formation Free Energymentioning

confidence: 99%

Self-compensation due to point defects in Mg-doped GaN

2016

View full text Add to dashboard Cite

Using hybrid density functional theory, we address point defects susceptible to cause charge compensation upon Mg doping of GaN. We determine the free energy of formation of the nitrogen vacancy and of several Mg-related defects. The entropic contribution as a function of temperature is determined within the quasiharmonic approximation. We find that the Mg interstitial shows a noticeably lower free energy of formation than the Mg substitutional to Ga in p-type conditions. Therefore, the Mg impurity is amphoteric behaving like an acceptor when substitutional to Ga and like a double donor when accommodated in an interstitial position. The hybrid-functional results are then linked to experimental observations by solving the charge neutrality equations for semiconductor dominated by impurities. We show that a thermodynamic equilibrium model is unable to account for the experimental hole concentration as a function of Mg doping density, due to nitrogen vacancies and Mg interstitials acting as compensating donors. To explain the experimental result, which includes a dropoff of the hole concentration at high Mg densities, we thus resort to nonequilibrium models. We show that either nitrogen vacancies or Mg interstitials could be at the origin of the self-compensation mechanism. However, only the model based on interstitial Mg donors provides a natural mechanism to account for the sudden appearance of self-compensation. Indeed, the amphoteric nature of the Mg impurity leads to Fermi-level pinning and accounts for the observed dropoff of the hole concentration of GaN samples at high Mg doping. Our work suggests that current limitations in p-type doping of GaN could be overcome by extrinsically controlling the Fermi energy during growth

show abstract

“…This can explain the differences of the DAP band for the different samples studied. The differences in the DAP band shape observed between ours porous GaN layers and the p-type substrate seems to suggest the incorporation of Mg acceptors in the lower part of the porous layer that would diffuse from the substrate as a consequence of the deposition temperature used as pointed out before [32,33].…”

Section: Experimental and Samplesmentioning

confidence: 81%

Optical and structural characterisation of epitaxial nanoporous GaN grown by CVD

et al. 2017

View full text Add to dashboard Cite

In this paper we study the optical properties of nanoporous gallium nitride (GaN) epitaxial layers grown by chemical vapour deposition on non-porous GaN substrates, using photoluminescence, cathodoluminescence, and resonant Raman scattering, and correlate them with the structural characteristic of these films. We pay special attention to the analysis of the residual strain of the layers and the influence of the porosity in the light extraction. The nanoporous GaN epitaxial layers are under tensile strain, although the strain is progressively reduced as the deposition time and the thickness of the porous layer increases, becoming nearly strain free for a thickness of 1.7 μm. The analysis of the experimental data point to the existence of vacancy complexes as the main source of the tensile strain.

show abstract

Magnesium diffusion profile in GaN grown by MOVPE

Cited by 38 publications

References 19 publications

Migration of Mg and other interstitial metal dopants in GaN

Migration of Mg and other interstitial metal dopants in GaN

Self-compensation due to point defects in Mg-doped GaN

Optical and structural characterisation of epitaxial nanoporous GaN grown by CVD

Contact Info

Product

Resources

About