Abstract : This final report discusses a completely novel approach for generating THz frequency radiation that utilizes interband transitions and tunneling processes which can be induced simultaneously within double-barrier (DB) GaSb/InAs/GaSb broken-gap (BG) resonant-tunneling-diodes (RTDs). This DB-BG-RTD device will utilizes two distinct innovations. First, ultra-fast heavy-hole (HH) interband tunneling is leveraged to depopulate a lower, valence-band (VB) well-state E1 which then allows electrons resonantly injected into an upper conduction-band (CB) well-state E2 (i.e., center region of the RTD) to serve as the electron source for the light-generating recombination at small photonic energy differences E2 - E1 lying within the THz regime. Second, the associated electrons and holes pairs are spatially-delocalized (SD) by the RTD heterostructures which leads to a significant suppression of all degrading nonradiative recombination processes. These effects allow for large population inversions and optical gains that may be used in single DB-BG-RTD microdisk laser structures operating at near room temperature ( 280 K) to produce 1-10 mW in the 1-3 THz gap region, which is a substantial improvement to the existing state-of-the-art solid-state THz source technology (i.e., 0.1 mW). Furthermore, it is expected that novel quantum-dot DB-BG-RTD nanopillar-array architectures can be used to further reduce drive-current heating effects to achieve additional multiplication of the output power.