| AVS 54th International Symposium | |
| Nanometer-scale Science and Technology | Tuesday Sessions |
| Session NS-TuP |
| Session: | Nanometer-scale Science and Technology Poster Session I |
| Presenter: | A. Hozumi, National Institute of Advanced Industrial Science and Technology (AIST), Japan |
| Authors: | A. Hozumi, National Institute of Advanced Industrial Science and Technology (AIST), Japan H. Taoda, AIST, Japan T. Saito, AIST, Japan |
| Correspondent: | Click to Email |
Organosilane self-assembled monolayers (SAMs) have been widely applied to the artificial control of surface chemical functionalities. Among the various types of SAMs, both aldehyde (CHO)- and carboxy (COOH)-terminated SAMs are of particular interest owing to their chemical reactivities to biomolecules. Here, we report on the fabrication of microdomains composed of CHO- and COOH-terminated SAMs on a Si substrate covered with native oxide. The cleaned substrate was first exposed to a vapor of 12.5 vol % solution of triethoxysilylundecanal (TESUD) diluted with absolute toluene for 3 h at 403 K. This vapor phase treatment produced the CHO-terminated SAM on the native oxide/Si surface. The thickness of this SAM was estimated by ellipsometry to be about 1.2 nm. Next, some of the samples were irradiated for 1~60 min with 172 nm vacuum UV light in air. Due to this treatment, the hydrophobic surface became hydrophilic gradually with irradiation time. Although film thickness remained almost unchanged even after irradiation for 25 min, water-contct angle decreased from 86 degree to about 25 degree. Both contact angle and film thickness decreased markedly after aound 25 min and reached their minimum of 5 degree or less and 0.3 nm, respectively, at the irradiation time of 60 min. We further confirmed by X-ray photoelectron spectroscopy and attenuated total reflection spectroscopy, the irradiation time of 25 min was determined the optimum time to yield reproducible COOH-terminated SAM. Finally, the CHO-SAM was irradiated site-selectively through a photomask. As confirmed by lateral force microscopy, the microstructures composed of 5 micron x 5 micron square features photoprinted on the CHO-terminated SAM surface were clearly imaged through the friction force contrast between the photoirradiated and masked regions. The former regions were expected to have been converted to COOH-terminated SAM.