Electrical properties of amorphous and crystalline phases in electroluminescent ZnS:Mn, Cu, Cl films

Abstract

Thin ZnS:Mn, Cu, Cl films exhibiting dc electroluminescence of Mn+2 are prepared by a three step method involving: (i) evaporation of pure ZnS layer, (ii) dipping in CuCl solution, and (iii) evaporation of ZnS:Mn, Cl top layer. In order to obtain some information about the effects accompanying the electroluminescence, measurements of the conductance as a function of temperature, dc field and ac field frequency as well as capacitance‐voltage characteristic were carried out. The results indicate that hopping is the predominant mechanism in the conductivity of a virgin (unformed) ZnS: Mn, Cu, Cl layer while a field enhanced crystallization is responsible for forming, ageing, and the appearance of the dc electroluminescence at an appropriate stage of the forming process.

Point-Contact I-V Characteristics of the Electroluminescent ZnS:Mn,Cu Thin Films Studied by STM

“…The conductivity of thin ZnS:Mn,Cu films was studied previously by the authors in connection with the dc-electroluminescence [7,8].…”

“…Thin ZnS:Mn films were deposited on a glass substrate, previously provided with indium-tin-oxide, by thermal evaporation in vacuum of about 10 -4 Pa. Copper was introduced into the film through immersing it in aqueous solution of CuCl2 and then annealing at 673 K in vacuum to force an uniform dopant distribution and a stucture improvement. More details on the preparation of the samples can be found elsewhere [7].…”