Ultraviolet Light Exposure Effect on the Nanoscale Current-Voltage Characteristics of Bare and Silicate Nanoparticle Incorporated 3-aminopropyltrimethylsiloxane Films Deposited Using a Focus Ion Beam-Milled Atomic Force Microscopy Tip

Abstract:
Polysilicon wire (PSW) sensor with a sensing membrane of 3-aminopropyltrimethylsiloxan (γ-APTES) incorporated with polydimethylsiloxane (PDMS)-treated silica nanoparticles (NPs) (γ-APTES+NPs nanocomposite) deposited by a focus ion beam (FIB)-milled capillary atomic force microscopy (AFM) tip have been reported to have excellent biochemical sensing characteristics, and improved performance can be achieved after the sensing films being subjected to ultraviolet (UV) light illumination. While most of the research on γ-APTES is focused on its sensing characteristics and material properties, rarely have been discussed regarding its electrical characteristics. In this work, nanoscale current-voltage (I-V) characteristics of the FIB-milled capillary AFM tip deposited pure γ-APTES film and γ-APTES+NPs nanocomposite films with different γ-APTES/NPs mixed ratios were measured by using an AFM with a conductive tip as the top electrode. The I-V characteristics of the γ-APTES and γ-APTES+NPs films after UV illumination were also investigated. Our experimental results show that the nanoscale I-V curve of the γ-APTES-based films is similar to that of a typical dielectric film, and the nanoscale bulk leakage current decreases with the increase of the UV exposure time and the γ-APTES solution/NPs mixed ratios, while the breakdown voltage increases with increasing UV exposure time but decreases with the increase of γ-APTES solution/NPs mixed ratios.