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Semiconductor Physics, Quantum Electronics & Optoelectronics. 2007. V. 10, N 4. P. 077-080.
Degradation processes in encapsulated ZnS:Cu powder
electroluminescent phosphors
Uzhgorod National University, 46, Pidhirna str., 88000 Uzhgorod, Ukraine
E-mail: atr@mail.uzhgorod.ua
Abstract. In this paper we present experimental results of the studying degradation
processes in electroluminescent panels, prepared from encapsulated ZnS:Cu powder
phosphors and theoretical simulation of energy parameters for the phosphor. Energy band
diagrams ZnS, Cu 2 S, ZnS-Cu 2-x S heterojunction and Cu-ZnS metal-semiconductor
junction have been constructed and cohesive energies for Zn-S, Cu-S, Zn-O, Cu-O and
Zn-Cu bonds have been calculated by the method based on a linear combination of
atomic orbitals and pseudo-potential. Time dependences of brightness have been found to
adequately fit a two-component exponential dependence. The first part of the exponential
curve has been attributed to the diffusion processes taking place in Cu 2-x S, and the second
one to the diffusion of Cu in ZnS matrix.
Keywords: electroluminescence, ZnS:Cu powder phosphor, degradation, heterostructure,
electronic structure, cohesive energy.
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