Dielectric Modulated Bilayer Electrode Top Contact OTFT for Label Free Biosensing

Abstract

In this paper, dielectric modulated bilayer electrodes top contact organic field effect transistor (DMBETC-OTFT) is investigated as a biosensing device for label-free detection of biomolecules. The nanocavity used for biomolecule detection is created by etching the oxide in a conventional OTFT device. Neutral and charged biomolecules can be detected by the proposed device using their respective dielectric constants and charge densities. Subthreshold swing (SS), on-current (I ON ), and on-off current ratio (I ON /I OF F ) are the main biosensing performance characteristics computed and compared for different gate work function (φ m ) and cavity thickness (T gap ) for the proposed biosensor device. The change in drain current (I D ), as well as the I ON /I OF F ratio, have both been calculated to investigate the sensitivity of the proposed biosensor. The influence of the gate work function is also investigated to improve the sensitivity of the proposed device. According to the finding of this study, using a gate work function with a lower value results in a significant increase in sensitivity. For charged biomolecules (Q f = +1 × 10 12 cm −2 ) with dielectric constant of biomoecules (K = 12), the highest drain current sensitivity is 4.5 × 10 3 . The drain current sensitivity achieved is four times greater, when comparing the proposed device to the latest published work of metal controlled dielectric modulated OTFT-based sensor. The proposed device also has a high I ON /I OF F sensitivity of 4.60 × 10 2 when V GS = -3.0 V and V DS = -1.5 V. In light of its high sensitivity, low cost, and bio-compatibility, the DMBETC-OTFT biosensor holds great promise for the advancement of new demanding flexible biosensing applications.

Performance analysis of OTFT with varying semiconductor film thickness for future flexible electronics

“…Altering the thickness of the active layer used to create OTFTs is one method for enhancing their functionality. Due to charge localization, understanding the study of the semiconductor layer and the semiconductor-dielectric interface is crucial for enhancing device performance [8][9][10][11][12][13]. Defects at the interface level drastically reduce the device's performance.…”