Abstract: A van der Pauw (VDP) sensor comprising an electronic circuit electrically coupled to a surface, the surface comprising a type III-V material, and the electronic circuit measuring a sheet resistivity of the surface using a VDP technique. The VDP sensor may further comprise a macromolecule, such as a porphyrin, an oligonucleotide, a protein, a polymer or a combination thereof in contact with the surface. The VDP sensors may be arranged in an array of similar or different sensors. An electronic circuit electrically coupled to a type III-V material having a two-dimensional electron gas, such as InAs or InN, the electronic circuit measuring an electrical property of the type III-V material having a two-dimensional electron gas.

Abstract: GaN-based heterojunction field effect transistor (HFET) sensors are provided with engineered, functional surfaces that act as pseudo-gates, modifying the drain current upon analyte capture. In some embodiments, devices for sensing nitric oxide (NO) species in a NO-containing fluid are provided which comprise a semiconductor structure that includes a pair of separated GaN layers and an AlGaN layer interposed between and in contact with the GaN layers. Source and drain contact regions are formed on one of the GaN layers, and an exposed GaN gate region is formed between the source and drain contact regions for contact with the NO-containing fluid. The semiconductor structure most preferably is formed on a suitable substrate (e.g., SiC). An insulating layer may be provided so as to cover the semiconductor structure. The insulating layer will have a window formed therein so as to maintain exposure of the GaN gate region and thereby allow the gate region to contact the NO-containing fluid.

Abstract: GaN-based heterojunction field effect transistor (HFET) sensors are provided with engineered, functional surfaces that act as pseudo-gates, modifying the drain current upon analyte capture. In some embodiments, devices for sensing nitric oxide (NO) species in a NO-containing fluid are provided which comprise a semiconductor structure that includes a pair of separated GaN layers and an AlGaN layer interposed between and in contact with the GaN layers. Source and drain contact regions are formed on one of the GaN layers, and an exposed GaN gate region is formed between the source and drain contact regions for contact with the NO-containing fluid. The semiconductor structure most preferably is formed on a suitable substrate (e.g., SiC). An insulating layer may be provided so as to cover the semiconductor structure. The insulating layer will have a window formed therein so as to maintain exposure of the GaN gate region and thereby allow the gate region to contact the NO-containing fluid.