The need for blue and ultra-violet (UV) solid-state emitters and detectors has propelled the investigation of several wide-bandgap semiconducting materials y-CuCl is a wide-bandgap (Eg = 3 395eV at 4 K), direct bandgap, semiconductor material with a cubic zincblende lattice structure. A very large exciton binding energy (190meV), assures efficient exciton based UV emission at room temperature. Its lattice constant, acuci = 0 541 nm means that the lattice mismatch to Si (asi = 0 543 nm) is <0 5% implying that low defect-density heteroepitaxy of CuCl on Si should be possible. y-CuCl on Si - the growth of a wide-bandgap, direct bandgap, optoelectronics material on silicon substrate is a novel material system, with compatibility to current Si based electronic/optoelectronics technologies Poly crystal line y-CuCl thin films are grown on Si (111), Si (100), and glass substrates by physical vapour deposition X-ray diffraction (XRD) studies confirm that CuCl has a cubic zincblende structure with a preferred (111) orientation Importantly, chemical interactions between CuCl and Si are eliminated. Photoluminescence (PL) and cathodoluminescence (CL) results for CuCl, deposited on either (100) or (111) Si, reveal a strong room temperature Z3 excitonic emission at ~ 387nm We have developed and demonstrated the room temperature operation of an ultra-violet electroluminescent device fabricated by the growth of y-CuCl on Si Electroluminescence measurements confirm UV light emission at wavelengths of ~380nm and ~387nm, due to excitonic behaviour. A further emission occurs in the bandgap region at ~360nm. The most efficient solid-state emitters are p-n junctions, therefore research on the possibility of doping CuCl is of great interest. The impact on structural, optical and electrical properties of CuCl by incorporation of Zn for n-type doping, by coevaporation of CuCl and ZnCl2 is investigated. Electrical measurements indicate ntype conductivity with resistivity ~ 34Qcm.