Bulk preparation of transparent IGZO TFTs with CS gate dielectric as glucose sensor on a pilot line

Abstract

In this paper, the indium gallium zinc oxide (IGZO) thin-film transistors (TFTs) with chitosan (CS) gate dielectric are prepared by the conventional photolithography technique on a pilot line. As-prepared devices on 200 × 200 mm substrate is very uniform, and have good performance of high on/off drain current ratio ~ 10−6, low subthreshold swing ~ 0.24, low-threshold voltage ~ 0.20 V and high-visible light transmittance > 90%. The glucose oxidase is drop-cased on the CS gate dielectric surfaces to make fully transparent CS-based IGZO TFTs with sensitivity to glucose. It is found that the current noticeably changes with increasing glucose concentrations. Herein, the glucose detection range from 0.5 to 30 mM covers the normal range of human blood glucose concentration. Moreover, the response time for glucose sensing is < 10 s, which is effective in detecting glucose. The results suggest that the CS-based IGZO TFTs can be used to detect glucose and provides a simple process to achieve low-cost- and larger-area fabrication of biosensors.