Design, Fabrication And Characterization Of MgZnO UV Photodetectors Enhanced Via Quadrupole Plasmon Of Ag

Following the laser detection and infrared detection technology, ultraviolet (UV)detection technology is a new kind of detection technology which played animportant role in both of the military and civilian areas. It has been applicated inconvert communications, flame sensing, air and water purification, and missileplume sensing, etal. As the third generation detectors, the wide band band gapseminconductor detectors with compact dimensions, low weight have beenconsidered to replace the vacuum phototube and Si-based photomultiplier whichcould work without cooling system and additional light filters. Among thesemiconductor family, ZnO combined with Mg, which is a tunable band gapssemiconductor which is a very promising candidate for fabricating visible (VIS) andsolar-blind ultraviolet photodetectors. However, due to a big challange to realizehigh efficiency and steady p-type ZnO (MgZnO), many performance targets of itsUV detectors were not achieved design requirement. Thus, before the breakthroughin p-type doping of ZnO based materials, how to achieve a highly effective ZnObased UV detectors is becaming a hot topic. In the previous reports, surfaceplasmons have been widely used to improve the efficiency of photoelectronicdevices such as light-emitting diodes and solar cells.at visible or IR range based onthe dipole resonance, which is usually appear at visible or IR range. Therefore, itlimited its applications in ultraviolet regime due to a large energy separation between the metallic dipole and wide gap semiconductor. Although there are some reports onimprovement in UV detector responsivity via surface plasmon, but its internalmechanism is still not very clear.Thus, based on aforementioned hotspot and difficult questions of ZnO based UVphotodetectors, the following researches in this paper are carried out:1. Based the results of the FDTD simulations, we realized Ag hybridquadrupole resonance in the Ag nanoclusters in the UV regimeexperimentally. As previous report, the hybrid quadrupole with an activityas dipole could interact with UV emission directly, which provide a newway for the application of surface plasmon technology to the ultravioletregime.2. Realization of the strong coupling tunable hybridized quadrupole plasmonsand their coupling with excitons in ZnMgO/Ag system, which may lay asolid ground for the future applications of surface plsamon enhancedphotodetectors.3. We fabricated MgxZn1xO/Ag ultraviolet photodetectors which has a highwavelength (350nm) selectively enhancement propertity based on theprevious work.4. Realization of Self-powered Ultraviolet photodetectors based on theasymmetry metal-semiconductor-metal (Au-MgxZn1-xO-Au) structure withthe same metal Au for the first time. It is worthy of note that the asymmetrymetal-semiconductor-metal structure was found to be extensively applicablein fabricating other kind of semiconductor detectors. At last, we fabricateAu-MgxZn1-xO/Ag-Au decector with high responsivity, low dark current,and low energy consumption of the photoelectric conversion properties.