| AVS 54th International Symposium | |
| Nanomanufacturing Topical Conference | Tuesday Sessions |
| Session NM+TF-TuA |
| Session: | Nanomanufacturing of Materials |
| Presenter: | J.R. Liu, University of California at Los Angeles |
| Authors: | J.R. Liu, University of California at Los Angeles C.M. Tanner, University of California at Los Angeles E. Lan, University of California at Los Angeles B.S. Dunn, University of California at Los Angeles J.P. Chang, University of California at Los Angeles |
| Correspondent: | Click to Email |
Nano-sized crystalline bacterial cell surface layer (S-layer) proteins have the intrinsic property to reassemble into two-dimensional arrays with ordered pores of identical size onto solid supports,1 ideal as a template for nanoscale patterning. In this work, we demonstrated that, when combined with area selective atomic layer deposition (ALD), the reassembled S-layer proteins can be effective nanotemplates to pattern nano-sized dielectrics. S-layer proteins were reassembled on Si wafer from the solution containing protein units and CaCl2. Atomic force microscopy (AFM) and transition electron microscopy (TEM) images showed that the protein unit size and the pore diameter are about 10 nm and 5 nm, respectively. Octadecyltricholorosilane (ODTS) was used to modify the more hydrophilic protein surface since ODTS has been demonstrated to be an effective monolayer resist on a hydrophilic SiO2 surface toward ALD of HfO2.2 High-k oxides were only deposited in the pores built by the protein units by an area selective ALD after the S-layer nano-template was modified by ODTS. Attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR), contact angle measurement, and x-ray photoelectron spectroscopy (XPS) were employed to analyze the reassembling, modification, and removing process of S-layer proteins. FTIR analysis of the reassembled S-layer proteins before and after ODTS treatment revealed NH (3297 cm-1), CH3 (2968 and 2866 cm-1), CH2 (2922 cm-1), CO (1645 cm-1), and CN (1525 cm-1) from S-layer proteins, while the intensity of CH2 increased after modified by ODTS, due to the 17 CH2 groups in ODTS. The ODTS treated S-layer proteins surface became more hydrophobic, evident by a contact angle change from 59o to 84o for 2h and 101o for 40h. After cleaning, the peaks of NH (3297 cm-1), CH3 (2968 and 2866 cm-1), CH2 (2922 cm-1), CO (1645 cm-1), and CN (1525 cm-1) from S-layer proteins disappeared, confirming that S-layer proteins have been removed completely. The current-voltage (I-V) of oxide nanopatterns is characterized by a conductive AFM.
1 U. B. Sleytr, P. Messner, D. Pum, and M. Sara, Angew. Chem. Int. Ed., 1034-1054, 38, 1999.
2 R. Chen, H. Kim, P. C. Mclntyre, and S. F. Bent, Appl. Phys. Lett., 4017-4019, 84, 2004.