| Zinc oxide(ZnO)is a broadband semiconductor material with unique physical and chemical properties that make it one of the excellent materials for the preparation of photodetectors.In the preparation of ZnO UV detectors,the different electrode materials make the metal-semiconductor contact type into schottky and ohmic contacts,where ohmic contacts have low contact resistance and good current stability.Due to the low light absorption of ZnO UV photodetectors,local surface plasmas can be used to modify UV detectors with high spatial localisation properties and strong local field enhancement properties,making them one of the most effective means of improving the utilisation of incident light.ZnO is an ideal UV detector material,which can be used to modify the UV detector according to the needs of practical applications.In view of the long detection period,complicated operation,high cost and secondary contamination of the traditional water quality testing chemical analysis method,this thesis proposes a simple,effective and timely detection technique for water quality solutions based on spectral analysis,with the goal of achieving a preliminary investigation of ZnO UV photodetectors in water quality detection,by preparing different metal electrodes on the surface of ZnO to obtain a stable performance ZnO UV photodetector,using local surface equipartition excitations to effectively enhance the performance of the device.The main research results are as follows:(1)From the perspective of optimizing the contact characteristics between metal electrodes and ZnO films,three metal-semiconductor-metal(MSM)electrode structures of silver(Ag),aluminum(Al)and titanium(Ti)were successfully prepared on ZnO films to achieve good ohmic contact between the three metal electrodes and ZnO films.Annealing the prepared detectors to investigate the effect of different annealing temperatures on the performance of ZnO UV photodetectors with three metal electrodes.The performance of the ZnO UV photodetectors with different fork finger pairs was investigated,and the performance of the ZnO UV photodetectors with three metal electrodes was tested.The results show that the peak responsiveness of the annealed 15 pairs of fork fingers of the ZnO/Ag,ZnO/Al and ZnO/Ti UV photodetectors is 0.59 A/W,0.38 A/W and 0.58 A/W respectively at 3 V bias.(2)From the perspective of enhancing the light absorption of the detector by exploiting the local surface equipartition excitonic resonance mechanism,modification work was successfully carried out by sputtering Pt nanoparticles on the surfaces of ZnO/Ag,ZnO/Al and ZnO/Ti UV photodetectors to prepare ZnO UV photodetectors with better optoelectronic performance.The sputtering of Pt nanoparticles on the detector at different times enhances the absorption of UV light by the detector and greatly improves the responsiveness of the device.Tests have shown that the sputtered Pt nanoparticle-modified ZnO UV photodetector exhibits several times greater responsiveness at the same bias voltage than the unmodified detector,showing better photoresponse performance.The sputtered 30 s Pt nanoparticle modified ZnO/Ag,ZnO/Al and ZnO/Ti UV photodetectors showed a 5.9,5.1 and 6.3 fold increase in peak responsivity at 3 V bias,with peak responsivities of 0.829 A/W,0.61 A/W and 1.028 A/W,respectively.(3)From the perspective of spectroscopy-based detection of water quality solutions without real-time,simple,rapid and low-cost,an innovative preliminary investigation of ZnO UV photodetector in water quality detection was carried out to broaden the application prospects of photoelectric detectors in water quality detection.The absorption spectra of different concentrations of potassium phthalate standard solution(COD standard solution)and turbidity standard solution(TURB standard solution)were tested,and then the water quality parameters of chemical oxygen demand(COD)and turbidity(TURB)of the solutions were detected by the ZnO UV photodetector.The results show that the response of the ZnO detector is linearly related to the COD and TURB concentrations,and that the ZnO detector can effectively detect trace substances in water solutions. |
