Tantalum oxide and nitride spectral features from a laser-produced plasma

Tantalum (Ta) is a transition metal with a unique combination of properties, and its alloys are found in a wide range of applications and fields (e.g., electronics, energy, chemical, transportation, defense, and space exploration fields). Relevant to all of these application areas is the detection of Ta or Ta-containing molecules. Laser-induced breakdown spectroscopy (LIBS) is a well-known elemental and isotopic analytical tool that involves the characterization of laser-produced plasmas (LPP) combined with optical emission spectroscopy. Here, time-resolved measurements of Ta I, TaO and TaN emission spectroscopic signatures from a laser-produced plasma are reported. Plasmas were generated using 1064 nm, 6 ns pulses from an Nd:YAG laser focused onto a pure Ta metal target in a gaseous environment with varying percentages of 02/N2 for controlling gas-phase oxidation/plasma chemistry. Time-resolved analysis showed that Ta oxide emission is prominent at later times in plasma evolution, whereas strong atomic emission is present at early times in air. Emission spectral features as a function of O
2
partial pressure showed that TaO emission intensity increases, while the peak intensity of TaO appears earlier with increasing O
2
availability. We also report emission spectra of TaN, and show that plasma chemistry favors TaO formation instead of TaN when O
2
is present in the environment.