Two-dimensional Gallium Nitride Research Articles

Thermal analysis of GaN HEMTs using nongray multi-speed phonon lattice Boltzmann method under Joule heating effect

Gallium Nitride (GaN) high electron mobility transistors (HEMTs) exhibit superior electrical properties for power and radio frequency applications, but performance is compromised by localized Joule heating, increasing channel temperatures. Precise thermal analysis during design is essential for optimizing device architecture and management strategies. Traditional methods like the Fourier heat diffusion equation (HDE) and the phonon lattice Boltzmann method (PLBM) with the D2Q8 scheme inadequately model phonon ballistic transport at high Knudsen numbers. This study introduces a nongray multi-speed PLBM integrated with the drift-diffusion model to analyze electro-thermal processes in GaN HEMTs. Validated through simulations of thermal conductivities in two-dimensional GaN thin films, the approach examines internal temperature rise in GaN HEMTs under different gate voltages, comparing results with HDE and gray BTE models, and emphasizing the need for non-Fourier effects in thermal analysis. It also evaluates the impact of GaN layer thickness on temperature distribution, providing a robust solution for thermal analysis in GaN HEMTs and other field-effect transistors.

Effect of in contents on the electronic and optical properties of 2D GaN/InxGa1-xN heterostructures

Two-dimensional gallium nitride (2D GaN) has recently received considerable attention due to its excellent physical properties, including high stability, wide and tunable bandgap, and magnetism. 2D GaN offers an accessible way to apply in photocatalytic hydrogen production as composing to vdW heterostructures. Here, we report a first principles study based on the HSE06 functional for the 2D van der Waals (vdW) GaN/InxGa1-xN heterostructures with a tunable bandgap achieved through modulation of indium (In) contents. Such heterostructure is a bilayer vertically stacked by a monolayer of GaN and a monolayer of InxGa1-xN, both of which are graphite-like structures. In particular, the heterostructure bandgap decreases from 3.37 eV to 2.23 eV as In content increases from 0 to 0.5, accompanying by a significant transition from indirect to direct band gap. All of the studied heterostructures have suitable band edge positions for the redox potential of water decomposition at pH 0. Furthermore, increasing In content improves the visible light absorption, carrier mobility and establishes a more effective built-in electric field in the heterostructures. Our results prove that 2D GaN/InxGa1-xN heterostructure is highly suitable as a catalyst for photocatalytic water splitting and provides theoretical guidance for applying 2D GaN in photocatalytic hydrogen production.

Free-standing 2D gallium nitride for electronic, excitonic, spintronic, piezoelectric, thermoplastic, and 6G wireless communication applications

Two-dimensional gallium nitride (2D GaN) with a large direct bandgap of ~5.3 eV, a high melting temperature of ~2500 °C, and a large Young’s modulus ~20 GPa developed for miniaturized interactive electronic gadgets can function at high thermal and mechanical loading conditions. Having various electronic, optoelectronic, spintronic, energy storage devices and sensors in perspective and the robust nature of 2D GaN, it is highly imperative to explore new pathways for its synthesis. Moreover, free-standing sheets will be desirable for large-area applications. We report our discovery of the synthesis of free-standing 2D GaN atomic sheets employing sonochemical exfoliation and the modified Hummers method. Exfoliated 2D GaN atomic sheets exhibit hexagonal and striped phases with microscale lateral dimensions and excellent chemical phase purity, confirmed by Raman and X-ray photoelectron spectroscopy. 2D GaN is highly stable, as confirmed by TGA measurements. While photodiode, FET, spintronics, and SERS-based molecular sensing, IRS element in 6G wireless communication applications of 2D GaN have been demonstrated, its nanocomposite with PVDF exhibits an excellent thermoplastic and piezoelectric behavior.

Effect of different valence cation vacancies and interstitial H on the photocatalytic performance of two-dimensional GaN:(O/C)

The effects of point defects on the physical properties of gallium nitride (GaN) monolayer surfaces have been widely reported in experimental and theoretical computational studies. However, the effects of different valence states of VGa and O/C and interstitial H co-doping on the photocatalytic properties of two-dimensional (2D) GaN surfaces have been rarely reported. Experimental studies on GaN based on Metal Organic Chemical Vapor Deposition and Vacuum Coating methods often overlook the unintentional existence of interstitial H in Ga vacancy. The structure, stability, and main affecting factors of the photocatalytic performance of Ga35MHiN35 (VGa3−/VGa2−/VGa1−/VGa0) (M = O/C) 2D surfaces were investigated to solve the present problem by using a generalized gradient approximation of the plane wave supersoft pseudopotential + U in the framework of density generalization theory. Results show that the 2D surface of Ga35MHiN35(VGa3−/VGa2−/VGa1−/VGa0) (M = O/C) is more stable under N-rich conditions, and the surface is more easily doped. Analysis of the electric dipole moment, effective mass, optical properties, and redox reactions of the doped surfaces reveals that the 2D surface of Ga35CHiN35 (VGa3−) has the best carrier activity, the best absorption spectral redshift, the longest carrier lifetime, and the strongest redox ability. Therefore, the 2D surface of Ga35CHiN35(VGa3−) is best as a photocatalyst. This work facilitates the preparation of new 2D GaN photocatalysts.

Transition Metal-Free Half-Metallicity in Two-Dimensional Gallium Nitride with a Quasi-Flat Band.

Two-dimensional half-metallicity without a transition metal is an attractive attribute for spintronics applications. On the basis of first-principles calculation, we revealed that a two-dimensional gallium nitride (2D-GaN), which was recently synthesized between graphene and SiC or wurtzite GaN substrate, exhibits half-metallicity due to its half-filled quasi-flat band. We found that graphene plays a crucial role in stabilizing a local octahedral structure, whose unusually high density of states due to a flat band leads to a spontaneous phase transition to its half-metallic phase from normal metal. It was also found that its half-metallicity is strongly correlated to the in-plane lattice constants and thus subjected to substrate modification. To investigate the magnetic property, we simplified its magnetic structure with a two-dimensional Heisenberg model and performed Monte Carlo simulation. Our simulation estimated its Curie temperature (TC) to be ∼165 K under a weak external magnetic field, suggesting that transition metal-free 2D-GaN exhibiting p orbital-based half-metallicity can be utilized in future spintronics.

Exploration on performance of two-dimensional GaN photocathodes with uniform-doping and variable-doping structure

In this paper, the properties of two-dimensional (2D) gallium nitride (GaN) photocathodes with a uniform doping and variable doping structure are studied by using Mg as a doping element based on first principles. The stability, bandstructure, work function, density of state and optical properties of the GaN bilayer and GaN trilayer in two-doped ways are investigated. The results show that formation energy of variable doping structure is less than that of the uniform doping structure, which means that the variable doping structure is more stable. At the same time, the formation energy increases with increase of layers. The pristine GaN bilayer has an indirect bandgap, while the doped GaN bilayer transforms into a direct bandgap. The impurity levels appear in a forbidden band of doped GaN trilayers, which is favorable for electron transition. The results of work function reveal that variable doping structure has lower vacuum barriers and more electron escape numbers, which proves that it can improve the quantum efficiency of photocathodes. Finally, the analysis of optical properties shows that the uniform doping structure has better optical properties than that of the variable doping structure.

Electronic structures and transport properties of low-dimensional GaN nanoderivatives: A first-principles study

Low-dimensional gallium nitride (GaN) nanoderivatives have recently attracted great attention, and they are one of the most attractive fields for future development of microelectronic devices. Here, the electronic structures and transport properties of GaN nanoderivatives were investigated by density functional theory. For two-dimensional bilayer GaN nanosheets, we found that AA-NN(GaGa) is the most stable structure among the five GaN stacking structures, and the stacking arrangement does not change the wide and indirect band gap of these two-dimensional bilayer stacked nanosheets. The transport properties of one-dimensional GaN nanoribbons were also investigated. The current in the bilayer GaN nanodevices was about twice that in the monolayer GaN nanodevices regardless of the nanoribbon morphology. That is, the bilayer GaN nanodevices show the current superposition law, like a parallel circuit, compared with their respective monolayer GaN model devices. The one-dimensional armchair boundary GaN nanoribbon devices showed the width effect because the width had a great effect on the current–voltage (I-V) curve and transport characteristics, but the one-dimensional zigzag boundary GaN nanoribbon devices did not and the I-V characteristic curves for different nanoribbon widths were similar. These extraordinary electronic structures indicate that GaN is promising for application in microelectronic devices.

The exceptionally high thermal conductivity after ‘alloying’ two-dimensional gallium nitride (GaN) and aluminum nitride (AlN)

Alloying is a widely employed approach for tuning properties of materials, especially for thermal conductivity which plays a key role in the working liability of electronic devices and the energy conversion efficiency of thermoelectric devices. Commonly, the thermal conductivity of an alloy is acknowledged to be the smallest compared to the parent materials. However, the findings in this study bring some different points of view on the modulation of thermal transport by alloying. The thermal transport properties of monolayer GaN, AlN, and their alloys of Ga x Al1−x N are comparatively investigated by solving the Boltzmann transport equation (BTE) based on first-principles calculations. The thermal conductivity of Ga0.25Al0.75N alloy (29.57 Wm−1 K−1) and Ga0.5Al0.5N alloy (21.49 Wm−1 K−1) are found exceptionally high to be between AlN (74.42 Wm−1 K−1) and GaN (14.92 Wm−1 K−1), which violates the traditional knowledge that alloying usually lowers thermal conductivity. The mechanism resides in that, the existence of Al atoms reduces the difference in atomic radius and masses of the Ga0.25Al0.75N alloy, which also induces an isolated optical phonon branch around 18 THz. As a result, the scattering phase space of Ga0.25Al0.75N is largely suppressed compared to GaN. The microscopic analysis from the orbital projected electronic density of states and the electron localization function further provides insight that the alloying process weakens the polarization of bonding in Ga0.25Al0.75N alloy and leads to the increased thermal conductivity. The exceptionally high thermal conductivity of the Ga x Al1−x N alloys and the underlying mechanism as revealed in this study would bring valuable insight for the future research of materials with applications in high-performance thermal management.

Tuning the electronic and optical properties of two-dimensional gallium nitride by chemical functionalization

Abstract A novel gallium nitride (GaN) monolayer was investigated and predicted for the application in optoelectronic devices by first-principles calculations. The GaN monolayers with hydrogenation or fluorination are mechanically and thermodynamically stable except the half-fluorinated one. It is noted that their electronic structure with adjustable band gaps could be easily modified by chemical functionalization. The electronic and optical properties of half-hydrogenated GaN monolayer evidence narrowed band gap and enhancement of visible-light absorption. These results provide the guidance for fabrication of optoelectronic devices based on GaN monolayer.

Tuning the physical properties of two-dimensional GaN via adsorption by the groups IIIA-VIIA atoms

We explore a first-principles study of the structural, electronic, magnetic, and optoelectronic properties of two-dimensional (2D) gallium nitride (GaN) adsorbed by the groups IIIA-VIIA atoms. Our calculations reveal that the chemisorption occurs for all selected adatoms and the adsorption energy of C is the highest because of its special adsorption configuration. The electronic structure studies indicate that the adatoms introduce magnetic feature with spin-polarized properties except for the group VIA atoms. Moreover, a semiconducting state presents in the groups IIIA, IVA and VIA atoms adsorbed 2D GaN, while a half-metallic state appears in 2D GaN after the adsorption of VA and VIIA atoms, which makes the latter higher work functions. Such regular modifications in physical properties of 2D GaN induced by adsorption could potentially allow use of this material in diverse electronic, optoelectronic, and spintronic applications.

Exploration of n- and p-type doping for two-dimensional gallium nitride: charged defect calculation with first principles

The calculation of charge transition energy level (CTL) and defect formation energy are of significance to explore potential n-type or p-type doping in materials. Based on the first-principles method, this paper systematically studied the structural, magnetic, and defect properties of 12 kinds of dopants in the two-dimensional hexagonal gallium nitride (2D h-GaN) system. The results show that the most stable charge states (MSCSs) for n-type systems are 0 and 1+, and all the n-type substitutes act as shallow donors. The MSCSs of the p-type systems are 1−, 0 and 1+, and the acceptor ionization energy is distributed higher than the valence band maximum (VBM) from ~1.25 to 2.85 eV, acting as deep acceptors, which will capture electrons (holes) in n-(p-type) 2D h-GaN and affect the carrier conductivity. Thus, it is difficult to achieve p-type doping through a single defect in 2D h-GaN, and complex defects are necessary to achieve p-type doping experimentally.

Electronic properties of two-dimensional G/GaN(SiC) van der Waals heterostructures

Based on the first-principles, the van der Waals heterostructures of two-dimensional gallium nitride (GaN) and silicon carbide (SiC) stacked graphene respectively have been researched. The G/GaN(SiC) heterostructure not only maintain the electrical properties of monolayer GaN(SiC), also keep the original electrical properties of graphene. Under the applied external electric field, the two heterostructures have their own Schottky contact critical transition points. When Eext > 0.10V/Å, both heterostructures are converted to ohmic contacts. In addition, in terms of biaxial strain, these two heterostructures maintain a good p-type Schottky barrier. The difference is that GaN in G/GaN turns into a direct bandgap within the biaxial strain range of −7% ~ −9%, while SiC in G/SiC always keeps the original indirect bandgap. The ohmic contact of G/GaN occurs at ε > 7%, while G/SiC occurs at ε > 5%. The charge injection of two heterostructures was further explored by analyzing the electrostatic potential under different biaxial strain. We believe that our work will make a significant contribution to future high-power high-voltage devices and Schottky devices.

(Invited) Atomic Resolution, Coordinated Electron Microscopy Characterization of 2D Layers Synthesized By Confinement Heteroepitaxy (CHet) Technique

Since the discovery of graphene in 2004 [1] there has been a flurry of activity in investigating two dimensional (2D) materials, because of their superlative properties: spin-orbit coupling, massless Dirac fermions, mechanical strength, thermal and chemical stability [2]. Remarkably, the in-plane hexagonal symmetry of graphene is largely responsible for its behavior. However, the zero-band gap of graphene presents hurdles to its use as a semiconductor. This has spurred interest in synthesis other van der Waals 2D structures, such as h-BN [3] and more recently 2D Gallium Nitride (2D GaN) [4].The synthesis of 2D Nitrides was first reported in 2016 by applying Confinement Heteroepitaxy (CHet) process to form a 2D Gallium Nitride (GaN) layer with 1-2 atom thickness. In this technique, a silicon carbide (SiC) substrate is graphitized and deliberately damaged using oxygen plasma to provide a two-step intercalation path. First a metal (like Gallium, or other group V metal) through evaporation is intercalated between the graphene and SiC substrate. Then, to complete the half reaction, nitrogen is introduced by ammonia annealing at 700 °C to form a 1-layer thick III-nitride.In this study, the growth method is extended from 2D GaN to variety of other 2D metals (Indium), Nitrides (InN) and alloys (InGa alloys). We employ a coordinated approach to understand the surface in both plan and cross-section view – linking through a variety of electron microscopy techniques, including auger electron spectroscopy (AES), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Bright-field, Dark-field, aberration-corrected STEM-HAADF imaging, and atomic-scale electron energy loss spectroscopy (EELS) mapping using a Gatan K2 SI direct electron detector and other techniques mapping were all applied to characterize the SiC/2D-layer/graphene interface. These electron microscopy techniques allow a precise, local measurement of the atomic structure of these new materials, including such growth parameters as the effect of graphene on the 2D layer stability, the effect of the SiC step edges on the layers structure, and the effect of the plasma type and source used in damaging the graphene on the 2D layer chemistry. Plasmon mapping also describes the unique bonding in the materials and their electronic structure. Ultimately, the measurements presented here characterize a whole new class of nanomaterials and provide insight on the fundamentals of the intercalation growth process. 1. Novoselov, K.S., et al., Electric field effect in atomically thin carbon films. Science, 2004. 306(5696): p. 666-669.2. Soldano, C., A. Mahmood, and E. Dujardin, Production, properties and potential of graphene. Carbon, 2010. 48(8): p. 2127-2150.3. Watanabe, K., T. Taniguchi, and H. Kanda, Direct-bandgap properties and evidence for ultraviolet lasing of hexagonal boron nitride single crystal. Nature Materials, 2004. 3(6): p. 404-4094. Al Balushi, Z.Y., et al., Two-dimensional gallium nitride realized via graphene encapsulation. Nature Materials, 2016. 15(11): p. 1166-1171. Figure 1

Strain-tunable electronic and magnetic properties of two-dimensional gallium nitride with vacancy defects

Based on density functional theory, we have investigated the effects of in-plane biaxial strain on the electronic and magnetic properties of the two-dimensional GaN (2D GaN) with Ga- (VGa) or N-vacancy (VN). We considered two different levels of vacancy concentration, i.e., θ=1/62 and θ=1/34. While the pristine GaN 2D structures are intrinsically semiconducting, the 2D GaN with VGa defects under tensile/compressive biaxial strains is metallic, except at a high compressive strain of 6%. In addition, the 2D GaN exhibits a strain-tunable magnetic property by introducing the VGa defects, where the magnetic moment can be modulated by applying a biaxial strain on the material. A compressive strain larger than 2% tends to suppress the magnetic effect. A drastic reduction of the total magnetization from 2.21 μB to 0.16 μB is clearly visible for a lower VGa concentration of θ=1/62. On the other hand, the 2D GaN with VN defects is nonmagnetic, and this behavior is not affected by the biaxial strain.

The influence of an AlN seeding layer on nucleation of self-assembled GaN nanowires on silicon substrates

Gallium nitride (GaN)-based nanowires (NWs) have attracted much attention for the fabrication of novel nanostructured devices. In this paper, the influence of an AlN seeding layer on the nucleation of self-assembled GaN NWs grown by plasma-assisted molecular beam epitaxy (MBE) on Si (111) substrates has been investigated. Not only is the formation of a two-dimensional compact GaN layer at the bottom of the NWs suppressed, but also a high density of vertically aligned well-separated GaN NWs originating from GaN islands are successfully obtained after introducing annealing and nitridation processes. Scanning electronic microscope and transmission electron microscope measurements show that the NWs have a high crystalline wurtzite structure nearly free of dislocations and stacking faults and the NW diameter remains constant over almost the entire length. Due to the temperature-dependent diffusion length of Ga adatoms during the nucleation process, the formation of well-separated NWs relies on the distribution and morphology of the underlying AlN seeding layer. Moreover, the SiNx layer served as mask to inhibit coalescence at the nucleation sites. The developed growth processes and the obtained results provide a viable path facilitating the use of MBE growth techniques to fabricate III-nitride NW-based materials and related devices on Si substrates.

Strong selective oxidization on two-dimensional GaN: a first principles study.

Ab initio calculations were performed to investigate the chemical oxidation of two-dimensional (2D) gallium nitride (GaN). The nitrogen surface was found to form a metastable configuration under oxygen adsorption, while the gallium surface could be readily transformed to a more stable configuration of HO-GaN-H with an exceptionally low energy barrier. The results also revealed that the adsorption of oxygen adatoms resulted in the reduction of work-function and induced the change from 2D GaN to a new GaNO compound. Our findings indicate that we should pay attention to the oxidation effect of 2D GaN in practical device applications.

Tuning the Electronic Properties of Hexagonal Two-Dimensional GaN Monolayers via Doping for Enhanced Optoelectronic Applications

We explore structural, electronic, and magnetic properties of two-dimensional (2D) gallium nitride (GaN) monolayer (ML) doped with different elements belonging to the groups III–VI, using density functional theory (DFT) with the Perdew–Burke–Ernzerhof (PBE) functional and the screened hybrid functional (HSE06) approaches as well as molecular dynamics (MD) simulations. Dopant interactions in Ga- and N-rich environments are investigated by varying their concentrations from 1.38 to 5.5%. Our calculations reveal that oxygen and aluminum impurities are the most preferred candidates under Ga- and N-rich conditions, respectively. The electronic structure studies indicate that dopants containing an even number of valence electrons introduce magnetic behavior with spin-polarized properties, or n-type conductivity with nonmagnetic features, depending on the stoichiometric III/V ratio during growth. Dopants with an odd number of valence electrons modify the GaN ML band structure from indirect to direct bandgap at the Γ point, depending on dopant types at different III/V ratios as well as substitutional site. The calculated charge transfer explains the dopants’ influence on the band structure and bond nature. The HSE calculations of doped g-GaN MLs show a 0.23–1.48 eV increase in the band gaps including the spin-polarized band structures when compared with their PBE values. MD calculations suggest high structural stability at high growth temperatures. Such dopant-induced modifications in structural and physical properties of 2D GaN ML could potentially allow use of this material in diverse electronic, optoelectronic, and spintronic applications.

Electronic and Optical Properties of Two-Dimensional GaN from First-Principles.

Gallium nitride (GaN) is an important commercial semiconductor for solid-state lighting applications. Atomically thin GaN, a recently synthesized two-dimensional material, is of particular interest because the extreme quantum confinement enables additional control of its light-emitting properties. We performed first-principles calculations based on density functional and many-body perturbation theory to investigate the electronic, optical, and excitonic properties of monolayer and bilayer two-dimensional (2D) GaN as a function of strain. Our results demonstrate that light emission from monolayer 2D GaN is blueshifted into the deep ultraviolet range, which is promising for sterilization and water-purification applications. Light emission from bilayer 2D GaN occurs at a similar wavelength to its bulk counterpart due to the cancellation of the effect of quantum confinement on the optical gap by the quantum-confined Stark shift. Polarized light emission at room temperature is possible via uniaxial in-plane strain, which is desirable for energy-efficient display applications. We compare the electronic and optical properties of freestanding two-dimensional GaN to atomically thin GaN wells embedded within AlN barriers in order to understand how the functional properties are influenced by the presence of barriers. Our results provide microscopic understanding of the electronic and optical characteristics of GaN at the few-layer regime.

(Invited) Realizing 2D Materials Via MOCVD

The last decade has seen nearly exponential growth in the science and technology of two-dimensional materials. Beyond graphene, there is a huge variety of layered materials that range in properties from insulating to superconducting. Furthermore, heterogeneous stacking of 2D materials also allows for additional “dimensionality” for band structure engineering. In this talk, I will discuss recent breakthroughs in two-dimensional atomic layer synthesis and properties, including novel 2D heterostructures and novel 2D nitrides. Our recent works include development of an understanding of substrate impact on 2D layer growth and properties, doping of 2D materials with magentic elements, selective area synthesis of 2D materials, and the first demonstration of 2D gallium nitride (2D-GaN). Our work and the work of our collaborators has lead to a better understanding of how substrate not only impacts 2D crystal quality, but also doping efficiency in 2D materials, and stabalization of nitrides at their quantum limit. Z.Y. Al Balushi, K.Wang, R.Krishna Ghosh, R.A. Vilá, S.M. Eichfeld, P.A. DeSario, D.F. Paul, J.D. Caldwell, S.Datta, J.M. Redwing, J.A. Robinson; Graphene stabilization of two-dimensional gallium nitride; arXiv preprint:1511.01871Eichfeld, S. M.; Hossain, L.; Lin, Y.-C.; Piasecki, A. F.; Kupp, B.; Birdwell, A. G. G.; Burke, R. A.; Lu, N.; Peng, X.; Li, J.; et al. Highly Scalable, Atomically Thin WSe2 Grown via Metal-Organic Chemical Vapor Deposition. ACS Nano 2015.Y.C. Lin, C.-Y. Chang, R. Ghosh,J.Li, H.Zhu, R.Addou, B.Diaconescu, T.Ohta, X.Peng, N.Lu, M.J. Kim, J.T. Robinson, R.M.Wallace, T.Mayer, S.Datta, L.J. Li, J.A. Robinson; Atomically Thin Heterostructures based on Single-Layer Tungsten Diselenide and Graphene; Nano Letters M. S. Bresnehan, G. Bhimanapati, K. Wang, D.Snyder, J.A.Robinson; Impact of Copper Overpressure on the Synthesis of Hexagonal Boron Nitride Atomic Layers; ACS Appl. Mater. Interfaces, 6, 16755–16762 (2014)S.M. Eichfeld, C.M. Eichfeld, Y.C. Lin, L. Hossain, J.A. Robinson; Rapid, non-destructive evaluation of ultrathin WSe2 using spectroscopic ellipsometry; APL Materials 2 (9), 092508Y.C. Lin, N. Lu, N. Perea-Lopez, J. Li, C.H. Lee, Z.Lin, P.N. Browning, M.S. Bresnehan, L. Calderin, M.J. Kim, T.S. Mayer, M. Terrones, J.A. Robinson; Direct Synthesis of van der Waals Solids on Epitaxial Graphene; ACS Nano 8 (4), 3715-3723 (2014)

Two-dimensional gallium nitride realized via grapheneencapsulation.

The spectrum of two-dimensional (2D) and layered materials 'beyond graphene' offers a remarkable platform to study new phenomena in condensed matter physics. Among these materials, layered hexagonal boron nitride (hBN), with its wide bandgap energy (∼5.0-6.0 eV), has clearly established that 2D nitrides are key to advancing 2D devices. A gap, however, remains between the theoretical prediction of 2D nitrides 'beyond hBN' and experimental realization of such structures. Here we demonstrate the synthesis of 2D gallium nitride (GaN) via a migration-enhanced encapsulated growth (MEEG) technique utilizing epitaxial graphene. We theoretically predict and experimentally validate that the atomic structure of 2D GaN grown via MEEG is notably different from reported theory. Moreover, we establish that graphene plays a critical role in stabilizing the direct-bandgap (nearly 5.0 eV), 2D buckled structure. Our results provide a foundation for discovery and stabilization of 2D nitrides that are difficult to prepare via traditional synthesis.