On Peculiar Sensitivity Trends of N-Channel Dielectric Modulated FET Biosensors

The orientation of biomolecules is known to affect the sensing performance of Dielectric Modulated Field Effect Transistor (DMFET) biosensors. However, the existing research lacks a comprehensive explanation and gives only limited insight into the sensitivity trends of such devices. This study elucidates how orientation changes the dominant sensing mechanisms for low and high dielectric constant biomolecules immobilized in the nanogaps. The results provide the first explanation for observed sensitivity trends and reason out the appearance of two different regimes in the sensitivity characteristics of an n-channel DMFET for DNA detection. Consequently, the findings, validated by TCAD simulations, offer new insights into the sensor's operation and contribute to advancing the understanding of these devices.