Interest in inorganic ternary nitride materials has grown rapidly over the past few decades, as their diversity of chemistries and structures make them appealing for a variety of applications. Due to synthetic challenges posed by the stability of N2, the number of predicted nitride compounds dwarfs those that have been synthesized, offering a breadth of opportunity for exploration. This review summarizes the fundamental properties and structural chemistry of ternary nitrides, leveraging metastability and the impact of nitrogen chemical potential. A discussion of prevalent defects, both detrimental and beneficial, is followed by a survey of synthesis techniques and their interplay with metastability. Throughout the review, we highlight applications (such as solid-state lighting, electrochemical energy storage, and electronic devices) in which ternary nitrides show particular promise.
Exploratory synthesis in novel chemical spaces is the essence of solid-state chemistry. However, uncharted chemical spaces can be difficult to navigate, especially when materials synthesis is challenging. Nitrides represent one such space, where stringent synthesis constraints have limited the exploration of this important class of functional materials. Here, we employ a suite of computational materials discovery and informatics tools to construct a large stability map of the inorganic ternary metal nitrides. Our map clusters the ternary nitrides into chemical families with distinct stability …
Binary III-N nitride semiconductors with wurtzite crystal structure such as GaN and AlN have been long used in many practical applications ranging from optoelectronic to telecommunication. The structurally related ZnGeN2 or ZnSnN2 derived from the parent binary compounds by cation mutation (elemental substitution) have recently attracted attention, but such ternary nitride materials are mostly limited to II-IV-N2 compositions. This paper reports on synthesis and characterization of zinc niobium nitride Zn2NbN3 - a previously unreported II2-V-N3 ternary nitride semiconductor. The Zn2NbN3 thin f…
Ternary nitride materials hold promise for many optical, electronic, and refractory applications yet their preparation via solid-state synthesis remains challenging. Often, high pressures or reactive gasses are used to manipulate the effective chemical potential of nitrogen, yet these strategies require specialized equipment. Here we report on a simple two-step synthesis using ion-exchange reactions that yield rocksalt-derived MgZrN$_2$ and Mg$_2$NbN$_3$, as well as layered MgMoN$_2$. All three compounds show nearly temperature-independent and weak paramagnetic responses to an applied magnetic…
A density functional theory study of atomic defects and dopants in ternary Z-phase transition-metal nitrides CrMN with M=V, Nb, or Ta is presented. Various defect formation energies of native point defects and of substitutional atoms of other metal elements which are abundant in the steel as well, are evaluated. The dependence thereof on the thermodynamic environment, i.e. the chemical conditions of a growing Z-phase precipitate, is studied and different growth scenarios are compared. The results obtained may help to relate results of experimental atomic-scale analysis, by atom probe tomograph…
We present a thorough theoretical study of ordering phenomena in nitride ternary alloys GaInN, AlInN, and AlGaN. Using the Monte Carlo approach and energetics based on the Keating model we analyze the influence of various factors on ordering in bulk crystals and epitaxial layers. We characterize the degree of both short range order (SRO) and long ranger order (LRO) for different compositions, temperatures and for substrates associated with different epitaxial strain. For the description of the SRO the Warren-Cowley parameters related to the first four coordination shells are used. The LRO is d…
Inorganic nitrides with wurtzite crystal structures are well-known semiconductors used in optoelectronic devices. In contrast, rocksalt-based nitrides are known for their metallic and refractory properties. Breaking this dichotomy, here we report on ternary nitride semiconductors with rocksalt crystal structures, remarkable optoelectronic properties, and the general chemical formula Mg$_{x}$TM$_{1-x}$N (TM=Ti, Zr, Hf, Nb). These compounds form over a broad metal composition range and our experiments show that Mg-rich compositions are nondegenerate semiconductors with visible-range optical abso…
We have investigated the effect of piezoelectric (PZ) polarization property on group velocity of phonons in binary as well as in ternary wurtzite nitrides. It is found that with the presence of PZ polarization property, the phonon group velocity is modified. The change in phonon group velocity due to PZ polarization effect directly depends on piezoelectric tensor value. Using different piezoelectric tensor values recommended by different workers in the literature, percent change in group velocities of phonons has been estimated. The Debye temperatures and frequencies of binary nitrides GaN, Al…
Condensed matter systems contain both fermionic and bosonic quasiparticles. Owing to the constraint imposed by the Fermi level, ideal material candidate for the emergent particles with higher-dimensional degeneracy manifold (i.e., nodal lines and nodal surfaces) has not been found in electronic systems. This paper demonstrates that according to the first-principle calculations and symmetry analysis, realistic ternary nitride Li$_6$WN$_4$ features ideal (nearly flat) nodal-surface and nodal-line structures in its phonon spectra. These nodal degeneracies are shaped like lanterns, and their exist…
Composition-dependent Thin-film Synthesis of Layered Ternary Iron Nitrides FeMN2 (M = W, Mo)
National Laboratory of the Rockies（落基山国家实验室）；Korea Advanced Institute of Science and Technology (KAIST)（韩国科学技术院）；Stanford University（斯坦福大学）；Colorado School of Mines（科罗拉多矿业学院）；Idaho National Laboratory（爱达荷国家实验室）
Computationally guided high-throughput synthesis is used to explore the Zn-V-N phase space, resulting in the synthesis of a novel ternary nitride Zn$_2$VN$_3$. Following a combinatorial PVD screening, we isolate the phase and synthesize polycrystalline Zn$_2$VN$_3$ thin films with wurtzite structure on conventional borosilicate glass substrates. In addition, we demonstrate that cation-disordered, but phase-pure (002)-textured, Zn$_2$VN$_3$ thin films can be grown using epitaxial stabilization on α-Al2O3 (0001) substrates at remarkably low growth temperatures well below 200 °C. The structural p…
Zinc-based nitride CaZn2N2 films grown by molecular beam epitaxy (MBE) with a plasma-assisted active nitrogen-radical source are promising candidates of next-generation semiconductors for light-emitting diodes and solar cells. This nitride compound has previously only been synthesized in a bulk form by ultrahigh-pressure synthesis at 5 GPa. Three key factors have been found to enable heteroepitaxial film growth: (i) precise tuning of the individual flux rates of Ca and Zn, (ii) the use of GaN template layers on sapphire c-plane as substrates, and (iii) the application of MBE with an active N-r…
The 4d-transition-metals carbides (ZrC, NbC) and nitrides (ZrN, NbN) in the rocksalt structure, as well as their ternary alloys, have been recently studied by means of a first-principles full potential linearized augmented plane waves method within the local density approximation. These materials are important because of their interesting mechanical and physical properties, which make them suitable for many technological applications. Here, by using a simple theoretical model, we estimate the bulk moduli of their ternary alloys Zr$_x$Nb$_{1-x}$C and Zr$_x$Nb$_{1-x}$N in terms of the bulk modul…
Rapid decline in fossil fuel energy necessitates the immediate need for renewable energy resources. Here, we report a previously unexplored class of nitrides AMN$_2$ keeping renewable energy applications in mind. Using a detailed structure and stability analysis using first principles simulation, we discovered twelve such compounds (few of which are already synthesized before), which are chemically, mechanically and dynamically stable. These twelve compounds were then evaluated for their suitability for three renewable energy applications, (i) photovoltaics, (ii) water splitting, and (iii) the…
The role of spontaneous and piezoelectric polarization in III-V nitride heterostructure devices is discussed. Problems as well as opportunities in incorporating polarization in abrupt and graded heterojunctions composed of binary, ternary, and quaternary nitrides are outlined.
Physical Properties and Thermal Stability of Zirconium Platinum Nitride Thin Films
ETH Zurich（苏黎世联邦理工学院）；Laboratory for Nanometallurgy, Department of Materials, ETH Zurich（苏黎世联邦理工学院材料系纳米冶金实验室）；Ion Beam Physics, Department of Physics, ETH Zurich（苏黎世联邦理工学院物理系离子束物理）
Chemical composition is the primary factor that determines the electronic band structure and thus also influences the optical properties of plasmonic ceramics including nitrides and oxides. In this work, the optical and plasmonic properties of TiN, ZrN and their hypothetical intermediate alloys Ti1-xZrxN (x= 0, 0.25, 0.50, 0.75, and 1), are studied by using first-principles density functional theory. We demonstrate the effects of electronic band structure tuning (band engineering) on the dielectric properties by varying the concentration of metallic constituents. Our calculations reveal that b…
Growing energy storage demands on lithium-ion batteries necessitate exploration of new electrochemical materials as next-generation battery electrode materials. In this work, we investigate the previously unexplored electrochemical properties of earth-abundant and tunable Zn1-xSn1+xN2 (x = -0.4 to x = 0.4) thin films, which show high electrical conductivity and high gravimetric capacity for Li insertion. Enhanced cycling performance is achieved compared to previously published end-members Zn3N2 and Sn3N4, showing decreased irreversible loss and increased total capacity and cycle stability. The…
Theoretical Insights into Inorganic Antiperovskite Nitrides (X$_3$NA; X = Mg, Sr, Ca, Ba; A = Sb, As): An Emerging Class of Materials for Photovoltaics
A two-dimensional (2D) monolayer of a novel ternary nitride Zn2VN3 is computationally designed, and its dynamical and thermal stability is demonstrated. A synthesis strategy is proposed based on experimental works on production of ternary nitride thin films, calculations of formation and exfoliation energies, and ab initio molecular dynamics simulations. A comprehensive characterization of 2D Zn2VN3, including investigation of its optoelectronic and mechanical properties, is conducted. It is shown that 2D Zn2VN3 is a semiconductor with an indirect band gap of 2.75 eV and a high work function o…
The spontaneous and piezoelectric polarizations of III-nitrides considerably affect the operation of various III-nitride-based devices. We report an ab initio study of the spontaneous polarization (SP) and piezoelectric (PZ) constants of the III-nitride binary and ternary alloys with the hexagonal reference structure. These calculated polarization properties offer us a profound principle for polarization engineering of nitride semiconductor devices, based on which we propose a few heterojunctions which have nearly-zero polarization effect at the junctions that can potentially enhance optical a…
Universal effect of ammonia pressure on synthesis of colloidal metal nitrides in molten salts
Pritzker School of Molecular Engineering, University of Chicago（芝加哥大学普里茨克分子工程学院）；Interdisciplinary Materials Science Program, Vanderbilt University（范德堡大学交叉材料科学项目）；Department of Chemistry and James Franck Institute, University of Chicago（芝加哥大学化学系和詹姆斯·弗兰克研究所）；Department of Chemistry, Northwestern University（西北大学化学系）；Center for Nanoscale Materials, Argonne National Laboratory（阿贡国家实验室纳米材料中心）；Department of Chemical and Biomolecular Engineering, Vanderbilt University（范德堡大学化学与生物分子工程系）
Transition metal nitrides have received significant interest for use within plasmonic and optoelectronic devices. However, deposition temperature remains a significant barrier to the integration of transition metal nitrides as plasmonic materials within CMOS fabrication processes. Binary, ternary and layered transition metal nitride thin films based on titanium and niobium nitride are deposited using High Power Impulse Magnetron Sputtering (HIPIMS). The increased plasma densities achieved in the HIPIMS process allow high quality plasmonic thin films to be deposited at CMOS compatible temperatu…
Are diffusion models ready for materials discovery in unexplored chemical space?
Korea Institute of Science and Technology (KIST)（韩国科学技术院）；Seoul National University（首尔大学）；Korea Institute of Ceramic Engineering and Technology (KICET)（韩国陶瓷工程技术研究院）；Korea Institute of Advanced Study（韩国高等研究院）；University of Science and Technology (UST)（韩国科学技术院）；Kumho Petrochemical（锦湖石化）
The nitride semiconductor materials GaN, AlN, and InN, and their alloys and heterostructures have been investigated extensively in the last 3 decades, leading to several technologically successful photonic and electronic devices. Just over the past few years, a number of new nitride materials have emerged with exciting photonic, electronic, and magnetic properties. Some examples are 2D and layered hBN and the III-V diamond analog cBN, the transition metal nitrides ScN, YN, and their alloys (e.g. ferroelectric ScAlN), piezomagnetic GaMnN, ferrimagnetic Mn4N, and epitaxial superconductor/semicon…
The control over the structural homogeneity is of paramount importance for ternary nitride compounds - the second most important semiconducting material-class after Si, due to its unrivalled applicability in optoelectronics, and high power/high frequency electronics. Therefore it is timely to investigate possible mechanisms influencing the crystallographic constitution of the material. In this work the diffusion mechanism of manganese in gallium nitride is investigated in two types of epilayers: Mn implanted metalorganic vapour phase epitaxy grown GaN and (Ga,Mn)N solid solution grown by molec…
Accelerated design of novel hard coating materials requires state-of-the-art computational tools, which include data-driven techniques, building databases, and training machine learning models against the databases. In this work, we present a development of a heavily automated high-throughput workflow to build a database of industrially relevant hard coating materials, such as binary and ternary nitrides. We use Vienna Ab initio Simulation package as the density functional theory calculator and the high-throughput toolkit to automate the calculation workflow. We calculate and present results, …
Ternary iron nitrides are of considerable interest due to their diverse magnetic properties. We find, based on first principles calculations, that the relatively minor structural distortion from the cubic antiperovskite structure in Fe$_3$GeN leads to unusual magnetic behavior. In particular, there is a separation into Fe sites with very different magnetic behaviors, specifically a site with Fe atoms having a stable local moment and a site where the Fe shows characteristics of much more itinerant behavior. This shows a remarkable flexibility of the Fe magnetic behavior in these nitrides and po…
In materials science, it is often assumed that ground state crystal structures predicted by density functional theory are the easiest polymorphs to synthesize. Ternary nitride materials, with many possible metastable polymorphs, provide a rich materials space to study what influences thermodynamic stability and polymorph synthesizability. For example, ZnZrN2 is theoretically predicted at zero Kelvin to have an unusual layered "wurtsalt" ground state crystal structure with compelling optoelectronic properties, but it is unknown whether this structure can be realized experimentally under practic…
The highly anisotropic thermal conductivity in layered materials is crucial for a broad range of applications such as thermal management of electronic devices, thermal insulation, and thermoelectrics. Understanding of anisotropic thermal transport in layered materials largely depends on atomistic simulations based on density functional theory (DFT) or empirical potentials, which however suffer either low computational efficiency or accuracy. Recently, machine learning interatomic potentials (MLIPs) are emerging as a powerful tool to bridge the gap. Despite the recent progress in developing MLI…
The II-IV-N$_2$ class of heterovalent ternary nitrides have gained significant interest as alternatives to the III-nitrides for electronic and optoelectronic applications. In this study, we apply first-principles calculations based on density functional theory to systematically investigate the effects of structural distortions due to cation size mismatch on the configurational disorder of the cation sublattice and the valence band structure in this class of materials. We find that larger size mismatch between the group-II and the group-IV cations results in stronger lattice distortions from th…
Despite the recognition of two-dimensional (2D) systems as emerging and scalable host materials of single photon emitters or spin qubits, uncontrolled and undetermined chemical nature of these quantum defects has been a roadblock to further development. Leveraging the design of extrinsic defects can circumvent these persistent issues and provide an ultimate solution. Here we established a complete theoretical framework to accurately and systematically design quantum defects in wide-bandgap 2D systems. With this approach, essential static and dynamical properties are equally considered for spin…
Hexagonal boron nitride (hBN) is an emerging two dimensional material for quantum photonics owing to its large bandgap and hyperbolic properties. Here we report a broad range of multicolor room temperature single photon emissions across the visible and the near infrared spectral ranges from point defects in hBN multilayers. We show that the emitters can be categorized into two general groups, but most likely possess similar crystallographic structure. We further show two approaches for engineering of the emitters using either electron beam irradiation or annealing, and characterize their photo…
Terahertz-permittivity of Carbon Nitrides: Revealing humidity-enhanced dielectric properties on the picosecond timescales relevant for charge carrier photogeneration
Hexagonal boron nitride (hBN)-long-known as a thermally stable ceramic-is now available as atomically smooth, single-crystalline flakes, revolutionizing its use in optoelectronics. For nanophotonics, these flakes offer strong nonlinearities, hyperbolic dispersion, and single-photon emission, providing unique properties for optical and quantum-optical applications. For nanoelectronics, their pristine surfaces, chemical stability, and wide bandgap have made them the key substrate, encapsulant, and gate dielectric for two-dimensional electronic devices. However, while exploring these advantages, …
Low-symmetry 2D materials---such as ReS$_2$ and ReSe$_2$ monolayers, black phosphorus monolayers, group-IV monochalcogenide monolayers, borophene, among others---have more complex atomistic structures than the honeycomb lattices of graphene, hexagonal boron nitride, and transition metal dichalcogenides. The reduced symmetries of these emerging materials give rise to inhomogeneous electron, optical, valley, and spin responses, as well as entirely new properties such as ferroelasticity, ferroelectricity, magnetism, spin-wave phenomena, large nonlinear optical properties, photogalvanic effects, a…
Low-cost graphene sponge electrodes were functionalized with two-dimensional (2D) materials, i.e., borophene and hexagonal boron nitride (hBN), using a one-step, hydrothermal self-assembly method. Borophene and hBN-modified graphene sponge anode and N-doped graphene sponge cathode were employed for electrochemical degradation of model persistent contaminants of emerging concern in one-pass, flow through mode, and using low-conductivity supporting electrolyte. Functionalization of the reduced graphene oxide (RGO) coating with 2D materials led to specific modifications in the electrode electroca…
