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III-Nitride materials such as gallium nitride (GaN) and indium nitride (InN) are critical for applications in electronics and optoelectronics due to their exceptional properties. However, their high-temperature stability is often limited by decomposition into constituent elements at low nitrogen pressures near or below ambient. This work investigates the use of nonequilibrium nitrogen plasma to stabilize GaN and InN at elevated temperatures and low pressures. Bulk nitride synthesis was demonstrated via plasma-assisted nitridation of Ga and In metals. Following synthesis, the suppression of nitride decomposition at temperatures exceeding the predicted equilibrium limits was accomplished by means of a nonequilibrium nitrogen plasma. Experimental results revealed that the nonequilibrium plasma imparted an additional chemical potential onto the ground state nitrogen by electron impact excitation, stabilizing GaN at 1000 °C and InN at 600 °C for nitrogen partial pressures as low as 10 Pa. With this experimental approach, the chemical potential of excited nitrogen species in the plasma was estimated to be 1.8 eV higher than the ground state value. These findings highlight the potential for plasma-based processing to enable scalable synthesis and stabilization of III-nitrides at high temperatures for advanced material applications. 

Abstract In this work, we demonstrate plasma‐catalytic synthesis of hydrogen and acrylonitrile (AN) from CH₄and N₂. The process involves two steps: (1) plasma synthesis of C₂H₂and HCN in a nominally 1:1 stoichiometric ratio with high yield up to 90% and (2) downstream thermocatalytic reaction of these intermediates to make AN. The effect of process parameters on product distributions and specific energy requirements are reported. If the catalytic conversion of C₂H₂and HCN in the downstream thermocatalytic step to AN were perfect, which will require further improvements in the thermocatalytic reactor, then at the maximum output of our 1 kW radiofrequency 13.56 MHz transformer, a specific energy requirement of 73 kWh kg_AN⁻¹was determined. The expectation is that scaling up the process to higher throughputs would result in decreases in specific energy requirement into the predicted economically viable range less than 10 kWh kg_AN⁻¹.