PNNL

Abstract

An accurate and routinely available method for stoichiometric analysis of thin films is a desideratum of modern materials science where a material's properties depend sensitively on elemental composition. We have thoroughly investigated femtosecond laser ablation inductively coupled plasma mass spectrometry (fs-LA-ICP-MS) as an analytical technique for determination of the stoichiometry of thin films down to the nanometer scale. The use of femtosecond laser ablation allows for precise removal of material with high spatial and depth resolution that can be coupled to an ICP-MS to obtain elemental and isotopic information. We have used molecular beam epitaxy-grown thin films of LaPd(x)Sb2 and T'-La2CuO4 to demonstrate the capacity of fs-LA-ICP-MS for stoichiometric analysis and its spatial and depth resolution. Here we demonstrate that the stoichiometric information of thin films with thickness ~ 10 nm or lower can be determined. Furthermore, our results indicate that fs-LA-ICP-MS provides precise information of the thin film-substrate interface and is able to detect the interdiffusion of cations.