Deep Ultraviolet Light Source from Ultrathin GaN/AlN MQW Structures with Output Power Over 2 Watt

High-output-power electron-beam (e-beam) pumped deep ultraviolet (DUV) light sources, operating at 230-270 nm, are achieved by adjusting the well thickness of binary ultrathin GaN/AlN multiple quantum wells. These structures are fabricated on high-quality thermally annealed AlN templates by metal-organic chemical vapor deposition. Owing to the reduced dislocation density, large electron-hole overlap, and efficient carrier injection by e-beam, the DUV light sources demonstrate high output powers of 24.8, 122.5, and 178.8 mW at central wavelengths of 232, 244, and 267 nm, respectively. Further growth optimization and employing an e-gun with increased beam current lead to a record output power of approximate to 2.2 W at emission wavelength of approximate to 260 nm, the key wavelength for water sterilization. This work manifests the practical levels of high-output-power DUV light sources operated by using e-beam pumping method.