Facile One‐step Synthesis of Zn_1–xMn_xSiN₂ Nitride Semiconductor Solid Solutions via Solid‐state Metathesis Reaction

Abstract

We report on the synthesis of the II‐IV‐N2 semiconductors ZnSiN2, MnSiN2, and the Zn1–xMnxSiN2 solid solutions by a one‐step solid‐state metathesis reaction. The successful syntheses were carried out by reacting the corresponding metal halides with stoichiometric amounts of silicon nitride and lithium azide in sealed tantalum ampoules. After washing out the reaction byproduct LiCl, powder X‐ray diffraction patterns were indexed with orthorhombic space group Pna21. Single phase products were obtained without applying external pressure and at a moderate reaction temperature of 700 °C. The resulting ZnSiN2 was found to consist of nano‐sized grains and needle‐shaped nano‐crystals. With increasing manganese content in the Zn1–xMnxSiN2 solid solution, we found the reaction product to be increasingly crystalline. Both the cell parameters and the bandgap values across the different compositions of the solid solutions change linearly. The sample Zn0.95Mn0.05SiN2 synthesized by means of solid‐state metathesis reaction is an intense red emitter with a broad emission maximum at λmax ≈ 619 nm when excited with ultraviolet light after annealing the sample at a pressure of 6 GPa and a temperature of 1200 °C.

Two-Step Solid-State Synthesis of Ternary Nitride Materials

“…To access more nitrogen-rich phases, reactions must proceed at low temperatures, where dinitrogen (N 2 ) formation is less thermodynamically favorable, or higher temperature reactions must change the effective chemical potential within the reaction system through use of high pressures or reactive gases, such as ammonia. Furthermore, a large number of potential binary metal nitride precursors are either refractory , or energetic, − which further reduces the number of useful reactions. Therefore, identifying sources of reactive nitrogen that yield desired products under mild conditions is imperative for advancement in nitride material discovery. …”

“…The presented reaction conditions are benign and can be performed in a traditional solid-state chemistry laboratory, thus increasing their utility in targeting other metal nitride compositions by multiple research groups. Previous studies on the synthesis of magnesium metal nitrides have employed custom high-pressure reactors, , or specialized deposition chambers. , By starting with the mixed anion Mg 2 NCl as a precursor, the reaction pathway does not proceed via a rapid propagation, as observed when starting with more energetic precursors, such as alkali azides or alkali-earth nitrides. , Furthermore, diffusion-limited products and binary metal nitrides observed in some metathesis reactions , are avoided. The presented reactions avoid toxic environments, such as ammonia or amide-based mineralizers, ,, that decompose under elevated temperatures and require careful safety considerations and custom equipment.…”

“… 25 , 26 By starting with the mixed anion Mg 2 NCl as a precursor, the reaction pathway does not proceed via a rapid propagation, as observed when starting with more energetic precursors, such as alkali azides or alkali-earth nitrides. 13 , 40 Furthermore, diffusion-limited products and binary metal nitrides observed in some metathesis reactions 40 , 41 are avoided. The presented reactions avoid toxic environments, such as ammonia or amide-based mineralizers, 21 , 42 , 43 that decompose under elevated temperatures and require careful safety considerations and custom equipment.…”

Low-Temperature Nitridation of Fe3O4 by Reaction with NaNH2

“… 18 Similar solid-state metathesis reactions have yielded various binary, ternary, and quaternary nitrides, recent examples being Mn 3 N 2 58 and Zn 1– x Mn x SiN 2. 59 The reaction between Fe 3 O 4 and NaNH 2 produced ε-Fe 2+ x N as the major product, but also a noncrystalline phase, as was also observed in the reaction with Fe 2 O 3. 18 We successfully crystallized this phase to yield a face-centered iron oxynitride, FeO 1– x N x (and γ″-FeN), as verified using 57 Fe Mössbauer spectroscopy.…”

Low-temperature synthesis of cation-ordered bulk Zn3WN4 semiconductor via heterovalent solid-state metathesis

“…32,33 These bulk methods have only produced fully nitridized phases when M is a main group element (i.e., LiZnN, Ca 2 ZnN 2 , Sr 2 ZnN 2 , Ba 2 ZnN 2 , ZnSiN 2 , ZnGeN 2 , ZnSnN 2 ). 28,[30][31][32][33][34][35][36][37][38][39][40] When transition metals are used in bulk syntheses, they tend to form sub-nitrides: e.g., Ti 3 ZnN 0.5 , V 3 Zn 2 N, Ti 2 ZnN, Mn 3 ZnN, and Fe 3 ZnN. [41][42][43][44][45][46] The nitrogen-poor nature of these materials stems from the challenges described above (i.e., N 2 stability, slow diffusion).…”