One-dimensional (1D) semiconductor field-effect transistors (FETs), with high surface-to-volume ratios, have been developed as label-free and ultra-sensitive chemical and biological sensors. In this work, we demonstrated a high-throughput and facile cleanroom-free nanolithography method to fabricate large-area and highly-aligned In2O3nanoribbons. Nanoribbon-based FET arrays were constructed over the centimeter scale, which was achieved by a low-temperature sputtering process combined with chemical lift-off lithography. Nanoribbon arrays of 350-nm width, 700-nm pitch, and 20-nm thickness were fabricated, and used as channel materials for FETs. These FETs showed high current on/off ratios &gt;107in the solid state and good performance in liquid-gating configurations with saturation behavior, low driving voltages, and low leakage currents. Different aspect ratio In2O3nanoribbons were fabricated, tested, and compared. The 350-nm nanoribbon FETs show higher pH sensitivity than 20-μm nanoribbons and thin-film FETs. Nanoribbons comprised of In2O3were functionalized with biotin to demonstrate streptavidin detection. Biotin detection at pM levels was achieved using urease enzyme activity as the amplification signal on 350-nm nanoribbon FETs, suggesting the possibility of nanoribbon FETs as platforms for enzyme-based sensing. We explored aptamer-based sensing using nanoribbon FETs where the channel semiconductors were functionalized with highly specific aptamers. Upon binding target molecules, such as the small-molecule neurotransmitter serotonin, target aptamers are hypothesized to alter electric fields near semiconductor surfaces, resulting in conductance changes in FETs. Serotonin-specific aptamer FETs were fabricated, tested, and compared, where 350-nm ribbons showed sensitivities down to fM concentrations for serotonin in high ionic concentration solutions. Wafer-scale In2O3nanoribbon transistor biosensors, fabricated by straightforward top-down fabrication processes, were demonstrated as a versatile sensing platform with high sensitivity, including pH, protein-based, and aptamer-based sensing, which are of great interest for next-generation ultra-sensitive biosensor platforms.

Fabrication of wafer-scale metal oxide nanoribbon field-effect transistor biosensors using chemical lift-off lithography

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.