| AVS 63rd International Symposium & Exhibition | |
| Thin Film | Thursday Sessions |
| Session TF2-ThM |
| Session: | Area-selective Deposition and Sequential Infiltration Synthesis |
| Presenter: | Leonidas Ocola, Argonne National Laboratory |
| Authors: | L.E. Ocola, Argonne National Laboratory D.J. Gosztola, Argonne National Laboratory A. Yanguas-Gil, Argonne National Laboratory A. Connolly, Vassar College |
| Correspondent: | Click to Email |
We have investigated a variation of atomic layer deposition (ALD), called sequential infiltration synthesis (SiS), as an alternate method to incorporate ZnO and other oxides inside polymethylmethacrylate (PMMA) and other polymers. The precursors used to synthesize ZnO in PMMA are water (H2O) and Diethylzinc (DEZ). SiS of ZnO in PMMA was accomplished by infiltrating (H2O:DEZ) cycles at 95 oC for periods of up to 4 min per cycle. Energy dispersive spectroscopy (EDS) results show that we synthesize ZnO up to 300 nm inside a PMMA film.
A key feature of an ALD process is the ability to add an atomic layer at a time. This characteristic allows for a detailed study of the formation of ZnO in the polymer matrix after each atomic step is formed. We followed each growth step of ZnO in PMMA using ex-situ photoluminescence (PL), Raman spectroscopy and x-ray photoemission spectroscopy (XPS). These studies show clear differences between mono, dimer and trimer Zn atom configurations. Mono Zn atoms (O-Zn and O-Zn-O) are formed with a single DEZ precursor pulse and one or two H2O pulses and exhibit pure UV emission with no evidence of oxygen vacancy states (VO). Dimer Zn atoms (O-Zn-O-Zn and O-Zn-O-Zn-O) are formed with two pulses of DEZ and two or three pulses of H2O. They do not form yet a continuous film as shown with Raman spectroscopy. Dimers do show strong PL emission from VO states In addition, XPS data show no evidence of ZnO wurtzite bonding. After 3 precursor cycles we observe first evidence of film formation inside the polymer matrix with Raman spectroscopy and wurtzite formation with XPS. The evolution of ZnO properties studied with PL, Raman and XPS from these initial stages up to 12 cycles of SiS ZnO will be presented. Such detailed study allows insight to growth mechanisms of ZnO in a non-traditional environment, which may lead to novel applications of ZnO as sensors or detectors.
This work was supported by the Department of Energy under Contract No. DE-AC02-06CH11357. Use of the Center for Nanoscale Materials was supported by the U. S. Department of Energy, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.