PNNL

Abstract

We report TaO and TaN emission spectroscopic signatures from a laser-produced plasma. Plasmas were generated using 1064 nm, 6 ns pulses from an Nd:YAG laser focused onto a pure Ta metal target in 1 atmosphere pressure with varying percentages of O2/N2 for controlling the 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 the air. Emission spectral features as a function of O2 partial pressure showed that TaO emission intensity increases, while the peak intensity of TaO is appeared earlier with increasing O2 availability. We also report TaN molecular spectra and show that thermo- and plasma chemical reactions lead to nitride molecular formation in a N2 gas environment, whereas Ta oxide molecular formation is favored when O2 is present.