Label-Free Biosensors Based on III-Nitride Semiconductors

Abstract

Chip-based biosensor devices received an increased attention for medical and pharmaceutical screening as well as for environmental monitoring. Most semiconductor devices such as the highly developed Si-based ISFET are, however, not sufficiently stable up to date. Due to their superior chemical stability in electro-lytes and their biocompatibility, group III-nitrides emerged as promising electronic transducer material for biosensors. Moreover, their transparency for visible light enables the simultaneous application of optical measurements, which are standard in biology and medicine. In this chapter, fabrication and properties of group III-nitride electronic biosensors are discussed with a main focus on AlGaN/GaN field-effect transistors. Using appropriate designs and functionalization, highly sensitive group III-nitride-based biosensors can be realized for a large variety of applications including detection of ions, biomolecules, toxins, deoxyribonucleic acid (DNA), proteins, and even explosives. In addition, other sensor concepts employing other members of the group III-nitride family (InN, AlN, and solid solutions) as well as alternative transducer concepts (optical, mechanical) are discussed shortly. Finally, the possibilities for the integration of such biosensors are addressed.