Paper PS-ThP25
Using Optical Emission and Broadband Absorption Spectroscopy to Elucidate Energy Partitioning Trends Within Inductively Coupled Plasma Systems

Thursday, November 10, 2016, 6:00 pm, Room Hall D

A fundamental understanding of interactions between plasma species is essential to characterizing complex plasma chemistry phenomena. By utilizing various optical spectroscopy techniques to probe internal energetics within nitrogen and oxygen-containing plasmas, we have elucidated energy partitioning information for both ground and excited state plasma species. Our approach focused initially on characterizing internal energies of N₂ within a simple homonuclear diatomic system (N₂). We then broadened our study to include the slightly more complex N₂O system and also a mixed gas plasma system (N₂ and O₂). In these systems, both N₂ and NO molecules can be studied. Optical emission spectroscopy (OES) and broadband absorption spectroscopy (BAS) techniques were employed to study internal energies of both excited and ground state species in all of these systems. Characteristic plasma energies (e.g. electron temperatures (T_e) and small molecule vibrational and rotational temperatures [T_vand T_r, respectively] were determined for species formed within each system. In most cases, T_v is significantly higher than T_r for molecules such as N₂ and NO, with T_v ranging from ~2000 K to >3000K and T_r having values between ~300 K and 1000 K. In general, vibrational and rotational temperatures show a strong positive correlation with applied rf power and often display a negative correlation with system pressure for the precursors studied. Deviations from these trends have also been investigated. Additional data from more complex systems used to modify a range of materials such as catalyst particles will also be presented. Collectively, these data enable insight into the properties of various plasma systems and the role energy partitioning plays in the assessment of plasma chemistry.