AlGaN/GaN based heterostructures are used to fabricate high electron mobility transistors for the purpose of a DNA hybridization sensor. Photodefinable PDMS is used to encapsulate the entire device except the gold sputtered gate area. The gold coated gate contacts are functionalized with thiolated ssDNA. The fabricated device is used to detect DNA hybridization of Salmonella DNA of two different concentrations of 1 μM and 4 μM. There is a higher drop in drain current when a higher DNA concentration is used. The device is also checked for reusability, thereby confirming the stability of the device and the encapsulation. The measurements are carried out at zero gate bias. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)