This book investigates the possibility to design and analyze a memory element using Gallium Nitride (GaN) based Heterojunction Field Effect Transistors (HFETs). The memory element uses a single transistor and zero capacitor. This memory takes advantage of the natural coexistence of both hole and electron gases in such heterojunction based devices. The two dimensional hole gas has been considered in the past as parasitic. It triggers hysteresis and transient effects within the FET output characteristics. Using this phenomenon, however, we propose an implementation of the memory concept in GaN/AlGaN/GaN HFET. The system is composed of the GaN/AlGaN/GaN regions.It may be integrated with conventional GaN HFET based technology as well. The present studies are performed using the ATLAS device simulator by Silvaco International.