Cathodoluminescent behaviour of sprayed ZnS specimens

Sprayed undoped and X-doped ZnS (with 4 at.% of X=Al, Sn) thin films prepared from chloride precursors are investigated. Their optimal deposition substrate temperature (Ts=773 K) leads to polycrystalline samples of both hexagonal (α) and cubic (β) phases with the predominance of the last one. The cathodoluminescence (CL) characteristics of ZnS and Al-ZnS films are similar. Their spectra depict a violet emission of 407 nm and a broad blue-green one at 524 nm due to chlorine impurities. Insertion of Sn2+ ions in ZnS material engenders SnCl2 and disappearance of the blue-green emission.