Skip to Main Content
In this work we present a novel depletion mode FET sensor that incorporates: 1) III-V semiconducting materials, 2) a hafnium oxide gate dielectric, and 3) direct immobilization of DNA to the surface. Our work differs from previously demonstrated FET biosensors that use doped silicon semiconductors with a silicon dioxide gate dielectric and complex crosslinking chemistry between the surface and the DNA. We hypothesize that depletion mode FETs are more sensitive, due to the lower density of states in the III-V materials (AlGaAs/InAlAs). Further, our novel method of directly immobilizing DNA onto the gate significantly simplifies sensor fabrication and brings DNA closer to the sensor surface. This places the majority of the DNA within one Debye length from the gate oxide surface, which potentially increases device sensitivity.