Modelling of Thin-film Transistor for Glucose Sensing Application

Electrochemical sensor exploiting thin-film transistor (TFT) technology has emerged as attractive candidate in the field of healthcare monitoring. Despite the remarkable advances in oxide TFT recently over large-area, simpler and low-cost fabrication, the fundamental study of TFT design and performance remains elusive for both practical application and upcoming development. In order to study the I- V characteristics of the TFT device for glucose sensing, a 2D model for n-type amorphous InGaZnO (a-IGZO) TFT is simulated using COMSOL Multiphysics. In this paper, the dependence of electrical characteristic of TFT on IGZO thickness and channel length are determined. It can be observed that the threshold voltage shifted negatively with increasing IGZO thickness and the drain current performance improves tremendously after reducing the channel length by half. As the glucose enzymatic reaction is adapted into TFT model, the effect of various glucose concentrations has been investigated on output characteristics, which shows the device able to detect glucose concentration ranging from 0.001 to 10 mmol/L. The high sensitivity of the device especially in terms of low limit detection could covers the glucose concentration between normal and diabetic patients, hence suggested the possibility of monitoring glucose level in the body.