Data‐Driven Investigation of Monosilane and Ammonia Co‐Pyrolysis to Silicon‐Nitride‐Based Ceramic Nanomaterials

Abstract

With its high strength, high thermal stability, low density, and high electrical resistance, silicon-nitride-based ceramics have been widely used as gate insulating layers, oxidation masks, and passivation layers. Employing SiN nanomaterials in anode applications also improves rate performances and cycling stability of the lithium-ion batteries. However, a fundamental understanding of the SiN synthetic process remains elusive. SiN gas-phase synthesis can be tailored with a comprehensive understanding of the underlying thermodynamics. In comparison to the characterization data available for solid-state SiN materials, high-level theoretical studies on gas-phase materials possessing SiÀ N bonds and comprehensive investigation of the SiN chemistry, particularly for nanoclusters, are very uncommon. Thus, we performed a theoretical study of Si and SiN alloy acyclic hydrides and polycyclic clusters to predict electronic structures and thermochemistry using quantum chemical calculation and statistical thermodynamics. Electronic properties by way of highest and lowest occupied molecular orbital energy gap and natural bonding orbitals analysis were calculated to explore the influence of elemental composition and geometry on the stability. Our studies provide characteristic data of SiN species for a data-driven approach to map the design space for discovery of novel silicon-nitride-based ceramic materials for advanced electronic and coating applications.

Deamidation reaction network mapping of pharmacologic and related proteins: impact of solvation dielectric on the degradation energetics of asparagine dipeptides

“…[25][26][27][28] This procedure was performed automatically using a modified version of the CalcK script previously employed by our group for reaction kinetics analysis. 29…”

“…The single-event parameters of the Arrhenius relationship, logIJA) and E A were obtained by fitting lnIJk) versus T −1 over the temperature range 298-1500 K. This procedure was performed automatically using a modified version of the CalcK script previously employed by our group for reaction kinetics analysis. [29][30][31][32][33][34][35][36][37][38][39][40] Through linear regression analysis, we determined Arrhenius behavior was obeyed well for all reactions. The solvation impact of liquid phase kinetics is beyond the scope of this work but will be addressed in future studies following the work of Jalan et al, which computes liquid-phase kinetics in relation to both the solute and the solvent.…”

Competitive Hydrogen Migration in Silicon Nitride Nanoclusters: Reaction Kinetics Generalized from Supervised Machine Learning

“…The extent of bond formation or bond decomposition along a reaction pathway was analyzed by the concept of bond order. This analysis has been used to investigate the molecular mechanism of chemical reactions mainly for gas-phase hydrocarbons with different functional groups; however, our group has had success for similar silicon nitride species . To examine the nature of the hydrogen migration (or shift) process, the Wiberg bond indexes have been calculated by using NBO 7.0 analysis as implemented in Gaussian16.…”

“…The harmonic frequencies and zero-point energy were scaled by factors of 0.96 and 0.98, respectively, to account for anharmonicity in the normal vibrational modes as suggested by Scott and Radom . It was reasonable to choose the G3//B3LYP level of theory since we have shown an excellent prediction for thermodynamic properties of hydrogenated silicon nitrides …”

“…45 It was reasonable to choose the G3//B3LYP level of theory since we have shown an excellent prediction for thermodynamic properties of hydrogenated silicon nitrides. 46 Using conventional statistical thermodynamics, partition functions based on the harmonic oscillator and rigid rotor approximations were used to calculate thermodynamic and kinetic properties as a function of temperature. The anharmonic effect can be quantified using the one-dimensional hindered rotor approximation.…”