ZnS:Mn, Dy yellow phosphors for White Light Emitting Diode were synthesized by a solid state reaction methodusing ZnS, MnSO4·5H2O, S and DyCl3·6H2O powders as starting materials. The mixed powder was sintered at 1000oC for 4h in an air atmosphere. The photoluminescence of the ZnS:Mn, Dy phosphors showed spectra extending from 480 to 700nm,peaking at 580nm. The photoluminescence of 580nm in the ZnS:Mn, Dy phosphors was associated with 4T1→6A1 transitionof Mn2+ ions. The highest photoluminescence intensity of the ZnS:Mn, Dy phosphors under 450nm excitation was observedat 4mol% Dy doping. The enhanced photoluminescence intensity of the ZnS:Mn, Dy phosphors was explained by energytransfer from Dy3+ to Mn2+. The CIE coordinate of the 4 mol% Dy doped ZnS:Mn, Dy was X=0.5221, Y=0.4763. Theoptimum mixing conditions for White Light Emitting Diode was obtained at the ratio of epoxy:yellow phosphor=1:2 formCIE coordinate.

Bi co-doped ZnS:Mn,Bi yellow phosphors for white light emitting diodes were prepared by the conventional solidstate reaction method. The optical and structural properties of ZnS:Mn,Bi phosphors were investigated by x-ray diffraction, scanning electro microscopy and photoluminescence. ZnS:Mn,Bi phosphors showed XRD patterns of hexagonal structure. The photoluminescence of ZnS:Mn,Bi phosphors showed spectra extending from 480 to 700 nm, peaking at 580 nm. The photoluminescence of 580 nm in the ZnS:Mn,Bi phosphors was associated with the 4T1 → 6A1 transition of the Mn2+ ions. The highest photoluminescent intensity of the phosphors under 405 nm and 450 nm excitation was obtained at Bi concentration of 7mol%. The optimum mixing conditions with epoxy and yellow phosphor for white light emitting diodes were observed in a ratio of epoxy:yellow phosphor of 1:3.5. The CIE chromaticity of the white LED at the 1:3.5 ratio was X = 0.3454 and Y = 0.2449.

Er을 첨가한 ZnS:Mn 형광체를 1000℃에서 4시간 고상반응법으로 소결하여 제조하였다. 결정 구조 및 광 특성은 XRD, PL 그리고 SEM을 통하여 분석하였다. XRD 결과, ZnS:Mn 형광체는 hexagonal 구조가 나타났고, Er의 농도가 증가함에 따라 Er2O3 구조가 관찰되었다. ZnS:Mn 형광체의 평균입자 크기는 약 15㎛였고, Er 첨가와 함께 ZnS:Mn, Er 형광체의 입자 크기는 감소하였다. 580nm 발광 피크는 ZnS:Mn, Er 형광체에서 Mn2+ 이온의 4T1→6A1으로의 전이에 의한 것이다. Er을 0.5mol% 첨가한 형광체의 발광 세기는 Er을 첨가하지 않은 ZnS:Mn 형광체보다 높았다. ZnS:Mn, Er 형광체에서 발광 세기의 증가는 Er3+에서 Mn2+로의 에너지 전이에 의한 것으로 생각된다.

A new technique to grow a manganese-doped zinc-sulfide(ZnS：Mn) has been proposed using the repeated deposition of the Hot Wall method. The optical characteristics and crystallinity for the ZnS and ZnS：Mn thin films deposited on a quartz glass substrate by the method were investigated. Also, The ZnS：Mn thin film elcetroluminescent devices were fabricated by the method to study luminescence characteristics. All films showed (111)-oriented cubic structure. By the repeated deposition, the deposition rates were decreased, and the optical characteristics and crystalline properties were improved, which clarifies that the method is effective to deposit the thin films with good crystallinity Futhermore, the crystallinity was more improved by the doping of Mn. Only one peak emission at around 585nm originating from Mn luminescent center is observed In the photoluminescent and electroluminescent spectra of ZnS：Mn films and the luminance of the ZnS：Mn-based thin film electroluminescent devices was obtained below 60cd/m2 . The optical and crystalline properties, luminescence characteristics are discussed in terms of the effects of the repeated deposition and Mn-doping.