Independence of elemental intensity ratio on plasma property during laser-induced breakdown spectroscopy.

The authors report that the elemental composition ratio of Ga to In in a CuIn(1-x)Ga(x)Se(2) compound semiconductor, a thin-film solar cell material, can be measured with little influence of plasma property changes by laser-induced breakdown spectroscopy (λ = 1064 nm, τ = 5 ns). It is shown that the similarity in excitation energy levels of the selected Ga and In emission lines and the fact that these elements belong to the same group of the periodic table are the critical factors ensuring the independence of intensity ratio on plasma conditions.