Selective assembly of DNA using DLC film as passivation layer for the application to nano-device

Deoxyribonucleic acid (DNA) can be used as an essential building block to construct nanometer-scaled electronic devices. It has been extensively investigated for application to nano-scale electronic devices. One problem in utilizing DNAs as conducting wires is to fix them at specific locations and align them with uniform intervals. We report an effective method to selectively align and uniformly separate λ-DNA molecules on a SiO2 surface using diamond-like carbon (DLC) thin film as a passivation layer. DLC was synthesized by RF plasma enhanced chemical vapor deposition (PECVD) with methane (CH4) and hydrogen (H2) gas. A photolithography process was also utilized to create alternatively line-pattern comprising an aminopropyltriethoxysilane (APS) region as an adhesion layer and DLC region as a passivation layer. The patterned sample was just dipped into the solution with DNAs and pulled out. DNA was attached only on the APS region defined by the amine groups, but not on the surface of the DLC region. Also, with the molecular combing method utilized in this work, DNA molecules were selectively aligned in parallel at 10 µm intervals on a SiO2 surface. Atomic force microscopy (AFM) was used to observe the DNA configuration.