| AVS 65th International Symposium & Exhibition | |
| Surface Science Division | Wednesday Sessions |
| Session SS+AS+EM-WeA |
| Session: | Semiconducting Surfaces |
| Presenter: | J. Trey Diulus, Oregon State University |
| Authors: | J.T. Diulus, Oregon State University R.T. Frederick, Oregon State University M. Li, Rutgers, the State University of New Jersey D.C. Hutchison, Oregon State University I. Lyubinetsky, Oregon State University L. Árnadóttir, Oregon State University M.R. Olsen, Oregon State University E.L. Garfunkel, Rutgers, the State University of New Jersey M. Nyman, Oregon State University H. Ogasawara, SLAC National Accelerator Laboratory G.S. Herman, Oregon State University |
| Correspondent: | Click to Email |
Solution-based organometallic nanoclusters are unique nanoscale material precursors due to the precise control over their size, shape, and structure. The interaction of photons with these clusters can result in the preferential removal of organic ligands at room temperature. This process leads to a change in solubility, which makes these materials prime candidates for next-generation photoresists for extreme ultraviolet (EUV) nanolithography. In this study, we are investigating the interaction of soft X-ray radiation with organotin based clusters to better understand the transition from organometallic to metal oxide nanoclusters. As a model system we are studying the charge neutral, sodium templated, butyl-tin Keggin (β-NaSn13) cluster [NaO4(BuSn)12(OH)3(O)9(OCH3)12(Sn(H2O)2)]. For analysis, the β-NaSn13 clusters were dissolved in 2-heptanone and spin-coated to form uniform thin films (~20 nm thick). Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) was used to measure the Sn 3d, O 1s, and C 1s core-levels, using photon energies above and below key absorption edges. These measurements allowed us to characterize changes in the both the atomic concentrations and chemical states of β-NaSn13 under a range of ambient conditions, including ultrahigh vacuum and multiple partial pressures (between 0.01 to 1 Torr) of oxygen, water, methanol, nitrogen, and hydrogen. Successive C 1s scans were collected during exposure to measure the change in intensity with respect to exposure time, ambient, and photon energy. A significant reduction in the C 1s signal was observed for oxygen ambients, suggesting the oxygen partial pressure was able to increase the rate of butyl group desorption from the β-NaSn13 clusters. Furthermore, a photon dose array was collected in each condition to determine whether ambient conditions have an effect on the photon induced chemistries leading to a solubility transition. The dose array was plotted as contrast curves, which indicate that an oxygen ambient significantly lowers the required photon dose relative to UHV. We also found that a water ambient significantly increases the required photon dose compared to an oxygen or UHV ambient. These studies ultimately improve the understanding of photon induced chemistries in the β-NaSn13 based thin films and provide mechanistic insights for the formation of tin oxide nanomaterials at surfaces.