摘要
研究了在薄膜电致发光器件中，ＺｎＳ∶Ｍｎ光学吸收边附近能带受电场的影响，通过对带边附近电致吸收的研究推导出薄膜电致发光器件发光层内存在局域电场。在电场作用下，ＺｎＳ薄膜的Ｆｒａｎｚ－Ｋｅｌｄｙｓｈ效应主要发生在带尾附近，带尾的局域态吸收受电场的影响引起的增加导致光学吸收边的红移。薄膜电致发光器件在强电场作用下，缺陷和杂质电离产生的局域化电场使得电场分布不均匀。当电场接近ＺｎＳ击穿强度时，薄膜的吸收系数随电场强度的变化偏离Ｆｒａｎｚ－Ｋｅｌｄｙｓｈ效应所遵循的指数关系。这是由于杂质和缺陷电离产生的局域电场导致发光层中的平均电场强度和外电加电压不成线性关系，此平均电场强度高于外电场强度。
In this paper, the effect of electric field on optical absorption edge of ZnS∶Mn thin films was studied through the measurementof electroabsorption of ZnS∶Mn thin film electroluminescence devices(TFELD). The results showed that Franz Keldysh effect of ZnS thin films resulted from electroabsorption of band tail. The shift of absorption edge to long wavelength was due to increase of absorption of local states near band edge. Under strong electric field, impurities and defects in phosphor of TFELD were ionized, which conduced to local electric field. When the applied voltage was very high and near breakdown voltage of TFELD, the relation of electroabsorption with applied voltage deviate from exponential relationship abided by Franz Keldysh effect. The reason was that, in high applied voltage, the average intensity of electric field was higher than that of external electric field for the ionization of impurities and defects.
出处
《功能材料》
EI
CAS
CSCD
北大核心
1997年第5期482-485,共4页
Journal of Functional Materials
