| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 94 === Abstract
Zinc sulfide (ZnS), as II-VI semiconductors with a wide band gap energy of 3.68eV,have received much attention due to their excellent luminescence properties and commercially used as phosphors applicated in electroluminescence devices. They are candidate materials for phosphors that emit visible light. The major and important applications of phosphors are used as light sources, display devices, radiation detectors and so on. Recently , the first of blue LED is patented by Nichia Chemical and then they use blue InGaN-based LED to excite YAG：Ce3＋-based phosphor, the yellow light emitting from the phosphor and the residual blue light produce the white light. Hence,solid white light sources are studied by industry and academia avidly.
Firstly , this report studies the luminescence of ZnS：Mn film and ZnS：Tm phosphors separately. ZnS：Mn film is deposited by the RF-magnetron sputtering system. We find the best of the luminescence is on Mn doping 1 mol%、annealing at 800℃. The PL of ZnS：Mn film results in the orange-yellow emission peaked at 576nm, and C.I.E（0.50,0.48）is obtained by the PL spectrum. We also find the intensity of the luminescence has a direct ratio with the intensity of XRD and has an inverse ratio with the FWHM；The roughness and the transmittance become the worse with the higher anneal temperature and the more dope. The band gap changes in the different of anneal temperature and dope；The band gap becomes large with the more dope and the higher anneal temperature, but it becomes small on Mn doping 3mol%.
ZnS：Tm phosphor has the best of the luminescence in Ar or in vacuum（~10-1 atm） is on Tm doping 2mol%、sintering 3 hr. In Ar, the PL of ZnS：Tm phosphor results in the narrow blue emission peaked at 472nm, and C.I.E（0.24,0.25）is obtained by the PL spectrum；In vacuum, the PL of ZnS：Tm phosphor results in the wide blue-green emission peaked at 500nm, and C.I.E is（0.21,0.32）. Although the luminescence red shifts to blue-green emission in vacuum, it is better in vacuum.
The approache patented by Nichia Chemical is limited due to wavelength conversion of the injected photon. So this report present a method through co-doping ZnS：Mn＋Tm（ZnS emites 450nm blue light、Tm emites 472nm blue light、Mn emites 580nm yellow light ）to produce the white light. But it takes little loss of energy because of no wavelength conversion of the injected photon. ZnS：Mn+Tm phosphor which is agreeable to the condition of white light in Ar or in vacuum（~10-1 atm） is on Tm doping 2mol%、Mn doping 0.075mol%. In Ar, the PL of ZnS：Mn+Tm phosphor results in the blue emission peaked at 470nm and the orange-yellow emission peaked at 583nm , and C.I.E（0.31,0.31）is obtained by the PL spectrum；In vacuum, the PL of ZnS：Mn+Tm phosphor results in the same emission , and C.I.E is（0.32,0.31）. And the luminescence is better in vacuum.
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