AbstractMaterials based on gallium nitride are characterized by a wide bandgap. The excellent chemical, physical and electronic properties give them a place in various fields: electronics, optoelectronics, photovoltaics, military, biological and medical. The use of biosensors based III‐N has been confirmed for the detection of biological substances in cells, blood or in solutions. This effect of detection results in various chemical and electric changes in a medium that is contacted with the devices without gate metallization of a high electron mobility transistor (HEMT). HEMT sensors can thus be used to detect gases, ions, pH values, proteins and DNA. In this work, we are interested in HEMT‐based heterostructure AlGaN/GaN used in the construction of biosensors. The principle of operation of the HEMT is based on the properties of a high‐mobility two‐dimensional gas (2DEG) and high‐speed saturation channel of a 2DEG AlGaN HEMT is very close to the surface that is very sensitive to absorption of analytes. We use this microsystem for detection of substances found in biological solutions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)