GaN High-Voltage Power Devices Joachim Wurfl AlGaN/GaN High-Electron-Mobility Transistors Grown by Ammonia Source Molecular Beam Epitaxy Yvon Cordier Gallium Nitride Transistors on Large-Diameter Si (111) Substrate Subramaniam Arulkumaran and Geok Ing Ng GaN-HEMT Scaling Technologies for High-Frequency RF and Mixed Signal Applications Keisuke Shinohara Group III-Nitride Microwave Monolithically Integrated Circuits Rudiger Quay GaN-Based Metal/Insulator/Semiconductor-Type Schottky Hydrogen Sensors Ching-Ting Lee, Hsin-Ying Lee and Li-Ren Lou InGaN-Based Solar Cells Ezgi Dogmus and Farid Medjdoub III-Nitride Semiconductors: New Infrared Intersubband Technologies M Beeler and E Monroy Gallium Nitride-Based Interband Tunnel Junctions Siddharth Rajan, Sriram Krishnamoorthy and Fatih Akyol Trapping and Degradation Mechanisms in GaN-Based HEMTs Matteo Meneghini, Gaudenzio Meneghesso and Enrico Zanoni