Research was carried out in order to develop successful technology for the production of zinc selenide and ZnSSe optoelectronic devices by metal organic vapour phase epitaxy (MOVPE). The optimum precursor combination for low temperature growth (T(G) ~330 C) of zinc selenide, ZnSSe, and ZnMgSSe has been identified as Me(2)Zn(NET(3)), t-Bu(2)Se, t-BU(2)S and (MeCp)(2)Mg. Halide was identified as the dominant n-type contaminant in the layers, and a novel halide-free route to t-Bu(2)Se was developed by Epichem. Nitrogen was successfully incorporated into zinc selenide using either plasma activation or the zinc precursors Zn[N(SiMe(3))(2)](2) or EtZnN(SiMe(3))(2). However, the layers were not p-type due to hydrogen passivation or a compensating n-type impurity (eg chlorine). Also, n-type doping was achieved using n-Butyl chloride. Lattice matched material ZnMgSSe was grown with excellent optical and structural properties. Optical and electron beam pumped blue green lasers at room temperature were demonstrated. In conclusion, only one important challenge remains: to obtain electrically active nitrogen. This may be achieved by improving the purity of existing precursors (ie removing halide contamination) or using alternative precursors which may provide the nitrogen in a mode active form (ie atomic nitrogen).