We report on the investigations of AlGaN/GaN field effect transistors with two lateral Schottky barrier gates on the sides of two dimensional electron gas. This kind of ―EdgeFETs‖ allowed us to efficiently control the current flow in the 2DEG conduction channel and form a nanowire which is beneficial for the adjustable resonant THz detection. Our studies of DC characteristics and properties in the sub terahertz frequency range confirm the validity of the experimental approach but show also some unexpected behaviors [1-3].  Terahertz radiation detection by junctionless metal-oxide-semiconductor field-effect transistors (JL MOSFETs) was studied and compared with THz detection using conventional MOSFETs. It has been shown that, in contrast to the behavior of standard transistors, the junctionless devices have a significant responsivity also in the open channel (low resistance) state. Working in the open channel state may be advantageous for THz wireless and imaging applications because of its low thermal noise and possible high operating speed or large bandwidth. It has been proven that the junctionless MOSFETs can also operate in a zero gate bias mode, which enables simplification of the THz array circuitry [3].  We show that the process of detection by GaN-Edge FETS and junctionless Si devices are similar and that both cannot be explained within the framework of the commonly accepted models [4] and requires a new theoretical approach. We discuss physical reasons of the phenomena indicating possible theoretical solutions.