Fabrication and Characterization of Self-Assembled Low Voltage Operated OTFT for H2S Gas Sensor for Oil and Gas Industry

Abstract

The article examines the low-voltage organic thin film transistor's (OTFTs) manufacturing and characterization process for hydrogen sulfide (H2S) gas sensing at room temperature and could be helpful at various emanating sites. The fabrication methodology utilizes a cost-efficient solution processed spin coating method for high-k dielectric (SrZrOx) as a gate oxide and floating film transfer method (FTM) for silver nanoparticles doped PBTTT-C14 film for the active semiconductor layer. The developed spin-coated dielectric film offers a high capacitance of 433 nF/cm2 with a high band gap of 4.95 eV. and also offers 0.1 nA/cm2 leakage current density, which clarifies that the dielectric film has very less numbers of pin holes suitable for good-performing OTFT. The surface morphology of the dielectric film shows a very smooth dielectric film (rms roughness 0.245 nm), which demonstrates a high-quality dielectric/semiconductor interface offered by the dielectric film for the high performance of the device. On the other hand, the low-cost FTM deposited silver nanoparticles doped PBTTT-C14 active layer film is quite uniform (30 ± 3 nm thickness) and free from any anisotropic effect, which further improves the device performance for sensing applications. The developed sensor is deliberately characterized for H2S gas sensor shows a sensing response of 80% at 5 ppm. The sensor passes with a low detection limit of 15.17 ppb and exhibits a relative shift of 47.7% over 5 ppm H2S gas in threshold voltage. The developed device can be used in various gas emanating sites and oil industries. © 1963-2012 IEEE.