A Comparative Investigation on Liquid-Based Memristor Sensor for Glucose Detection

This study reports a comparison of the behavior of liquid-based memristor sensors when tested with different concentrations of liquid glucose. A thin film of titanium dioxide (TiO2) serves as the sensing layer and is prepared through a sol-gel process using a spin coating method. This TiO2 layer has been spin coated on three sensors with a spin speed of 2000, 2500 and 3000 rpm respectively. A nine-well structure was patterned on the TiO2 layer for all three sensors. Four different concentrations of liquid D-glucose 10, 20, 30, and 40 mM were tested on this sensor. These memristor sensors were characterized using a Keithley 4200-SCS Semiconductor Characterization System for current-voltage (I-V) measurements. The experimental results show that the ROFF/RON (off-state resistance to on-state resistance ratio) increases as the glucose concentration increases in line with the increase in the spin speed of TiO2 sol-gel coating. The memristor sensor with the highest glucose concentration at the highest spin speed of 3000 rpm resulted in the highest ROFF/RON ratio of 2.25 and subsequently contributed to the highest sensitivity of 56.25 (mM)-1. In conclusion, increasing the spin speed of the TiO2 sol-gel coating will increase the ratio and thus increase the sensitivity of the sensor.