Room Temperature Electrically Driven Ultraviolet Plasmonic Lasers

Abstract Plasmonic lasers, which make use of the strong confinement of surface plasmon polaritons (SPPs), are key components to realize ultracompact coherent light sources at deep subwavelength scale. Currently, large metal and radiation losses of their metallic cavities limit electrically driven plasmonic lasers operation mainly at cryogenic temperature, where sufficient gain can be obtained. It is a crucial challenge to accomplish high performance electrically driven plasmonic lasers operated at room temperature. Benefiting from the large exciton binding energy and large oscillator strength of zinc oxide (ZnO) gain media, an optically pumped ultraviolet (UV) plasmonic laser is demonstrated from a hybrid metal–insulator–semiconductor structure, in which a magnesium oxide (MgO) gap layer plays a critical role in reducing the metallic loss. Further optimizing the thickness of the MgO gap layer and ZnO active layer, room temperature electrically driven UV plasmonic lasers with a threshold of 70.2 A cm^‐2 are realized for the first time under the injection of electrical carriers through the metallic electrode of the hybrid structure. Localizing light in subwavelength dimension, this novel type of UV plasmonic nanolasers may find various applications in photolithography, sensing, integrated microfluidic systems for surface sterilizations and nanoscale treatment processes.