Investigation On The Structural And Optical Properties Of AlN: Eu Thin Film And Related Materials

Rare earth ions doped AlN materials,due to excellent optical,magnetic,and electrical properties,are promising to be applied in many fields,such as detector,laser,lighting and display device,and diluted magnetic semiconductor.Therefore,it become one of appealing materials.In this thesis,the AlN thin films with the thickness of~290nm were grown on sapphires by Hydride Vapor Phase Epitaxy(HVPE).Then,the Eu,Tm,Pr,and Er ions were implanted into AlN layer.The series of samples cover the Eu ions single-doped AlN and Eu/Tm,Eu/Pr and Eu/Er co-doped AlN,as well as,Eu,Pr and Tm co-doped AlN.The content of elements was detected by Energy Dispersive Spectroscopy(EDX).The Raman and X-ray diffraction(XRD)were used to characterize the structural properties of samples.The optical properties were characterized by Cathodoluminescence(CL)and Photoluminescence(PL).The influence of doses of rare earth ion,annealing temperatures and co-doping on the structural and optical properties of rare earth ion doped AlN samples were investigated.The main results are as follows:1.The impact of annealing temperatures on content of oxygen element,structural properties and optical properties were investigated.It was found that the annealing temperature has great impact on the content of oxygen in AlN.Through EDX analysis,it can be concluded that the content of oxygen element decreases as the annealing temperature increases.When the AlN:Eu samples were annealed at 1040?,the stress induced by ion implantation was released.The emission intensity enhanced when AlN:Eu samples were annealed at 1000?,and then dropped with the temperature increasing.2.The influence of Eu doses on optical and structural properties of AlN:Eu samples were studied.The results show that the vacancies,which caused by Eu ion implantation with the fluence of 1×10~155 at/cm~2,can release the stress in AlN:Eu layer.With increasing annealing temperature,the enhancing emission intensity of Eu ions and decreasing emission intensity of defects can be observed.In low-temperature PL spectra,the abundant of emission lines were observed,which originated from the 4f-4f transition of Eu ion.The abundant emission peaks were assigned to the corresponding energy transition according to the change of emission intensity and peaks position with temperatures increasing.3.The energy transfer between Eu,Tm and Pr ions was found after the deep analysis of CL and PL spectra of AlN:Eu/Tm,AlN:Eu/Pr,AlN:Eu/Er and AlN:Eu/Pr/Tm samples.The energy just can be transferred from the Tm and Pr ions to Eu ions and from the Pr ions to Tm ions.The CIE chromaticity coordinate of rare earth ion co-doped AlN samples shift obviously with different ratio of rare earth ions dose.If the Pr ion doses were further added in AlN:Eu/Pr/Tm samples,the white light emitting can be achieved.4.The impact of sample temperature on photoluminescence properties of AlN:Eu/Pr samples was studied.With the temperature increases from 3.5 K to 280 K,the apparent falling of emission intensity of Eu and Pr ions and blue shift of the peak at 527nm of Pr ions and the peak at 545 nm of Eu ions were observed.At low temperature,the emission peaks at 604 and 625 nm was splitted.The light efficiency of material will be enhanced and the light color of material can be controlled by adjusting the doses and varieties of ions and annealing temperature.So,this work is of great significance in the field of lighting and full-color display.