Evaluation of tin nitride (Sn3N4) via atomic layer deposition using novel volatile Sn precursors

Abstract

Novel Sn precursors, Sn(tbip)(2), Sn(tbtp)(2), and Sn(tbta)(2), were synthesized and characterized using various analytical techniques and density functional theory calculations. These precursors contained cyclic amine ligands derived from iminopyrrolidine. X-ray crystallography revealed the formation of monomeric SnL2 with distorted seesaw geometry. Thermogravimetric analysis demonstrated the exceptional volatility of all complexes. Sn(tbtp)(2) showed the lowest residual weight of 2.7% at 265 degrees C. Sn3N4 thin films were successfully synthesized using Sn(tbtp)(2) as the Sn precursor and NH3 plasma. The precursor exhibited ideal characteristics for atomic layer deposition, with a saturated growth per cycle value of 1.9 & Aring; cy(-1) and no need for incubation when the film was deposited at 150-225 degrees C. The indirect optical bandgap of the Sn3N4 film was approximately 1-1.2 eV, as determined through ultraviolet-visible spectroscopy. Therefore, this study suggests that the Sn3N4 thin films prepared using the newly synthesized Sn precursor are suitable for application in thin-film photovoltaic devices.