Fabrication of monodisperse asymmetric colloidal clusters by using contact area lithography (CAL).
We report a new fabrication method of asymmetric colloidal clusters by using contact area lithography with site-selective growth. Nanometric surface patterns (approximately 44, 60, and 81 nm in diameter) were prepared by coating surfaces with self-assembled monolayers (SAMs; octadecyltrichlorosilane (OTS) in this study) except the contact area either between colloidal particles or between colloids and substrate. Nanoscale site-specific heterogeneous nucleation and growth of oxide materials of titanium were studied using the patterns of OTS-SAMs onto the either flat or curved surfaces of SiO2. Experimental results suggest that a combination of the large difference in the surface energy between the growing and surrounding surfaces and the diffusion-controlled growth leads to complete nanoscale site specificity. We also fabricated superstructrures of silica spheres with hemispheres of titania (<20 nm in dimension) on their surfaces and discussed the optical properties of colloidal films consisting of the monodisperse asymmetric colloidal clusters in terms of photonic band gap.
Bae
Changdeuck
C
Center for Materials and Processes of Self-Assembly, School of Advanced Materials Engineering, Kookmin University, Seoul 136-702, Korea.
Moon
Jooho
J
Shin
Hyunjung
H
Kim
Jiyoung
J
Sung
Myung M
MM