Study On Zinc Oxide Based Ultraviolet Random Laser And Surface Plasmon Enhanced UV Photodetector

Zinc Oxide（ZnO）is a semiconductor material with a wide band gap（3.37 eV）and a high exciton binding energy（60 meV）in Group II-VI.Compared with its material,it has shorter excitation wavelength and better luminescence performance,and its band gap corresponds to ultraviolet wavelength.Therefore,the development of ZnO based materials in the field of short wavelength lasers and UV detectors has a high potential in the field of luminescence and detection.but some properties of the devices need to be further improved.In the field of luminescence,ZnO thin films were prepared by magnetron sputtering to grow on sapphire Al₂O₃ substrates.On this basis,a ZnO based electrically pumped random laser device is designed.It is proved that the structure can produce low threshold random laser.In the field of detection,a ZnO based UV photodetector is designed and simulated by using COMSOL simulation software.The surface plasmon resonance（SPR）effect is applied to improve the photoelectric performance of the photodetector.The main results are as follows:（1）In this paper,Based on the ZnO nanoscale array generated by magnetron sputtering,an electrically pumped random laser with Au/ZnO/Au back-to-back Schottky structure has been fabricated.The low threshold laser emission of the ZnO based random laser has been realized.The threshold value is 2 A/cm²,the luminescence peak is randomly distributed between 375nm-400 nm and the minimum half-width is 2nm.Therefore,It is proved that the device fabricated by this method can generate random laser and its threshold value is relatively low.（2）In this paper,the theoretical design of zinc oxide ultraviolet detector based on subwavelength silver grating enhanced surface plasmon resonance（SPR）is realized by covering the dielectric layer with high folding rate on the surface of the device.The multi-physical field coupling simulation software of COMSOL finite element method is used.Through the simulation of the device,the absorption of ultraviolet light is realized at the wavelength of 368 nm.The optimum structure parameters are determined as follows:grating period is 210 nm,light incidence angle is 55°,refractive index of dielectric layer is 2.8,thickness is 140 nm,grating spacing is 100 nm,grating thickness is 80 nm.The maximum absorption multiplication factor of the device can reach 108.