gamma-CuCl is a wide-band gap (E-g = 3.395 eV at 4 K), direct band gap, semiconductor material with a cubic zincblende lattice structure. A very large exciton binding energy (190 meV), assures efficient exciton-based emission at room temperature. Its lattice constant, a(CuCl) = 0.541 nm means that the lattice mismatch to Si (a(Si) = 0.543 nm) is < 0.5%. gamma-CuCl on Si-the growth of a wide-band gap, direct band gap, optoelectronics material on silicon substrate is a novel material system, with compatibility to current Si-based electronic/optoelectronics technologies. Both n-type and p-type CuCl will be required for development of homojunction light-emitting diodes (LEDs). The authors report on the impact of incorporation of Zn for n-type doping of CuCl by co-evaporation of CuCl and ZnCl2. Polycrystalline Zn-doped gamma-CuCl thin films are grown on Si (1 1 1), Si (1 0 0), and glass substrates by physical vapour deposition. X-ray diffraction (XRD) studies confirm that this n-doped CuCl has a cubic zincblende structure with a preferred (1 1 1) orientation. Several excitonic bands are evident in low-temperature photoluminescence (PL) measurements such as the Z(3) free exciton at similar to 388 nm; I-1-bound exciton at similar to 392 nm and M free biexciton at similar to 393 nm. Cathodoluminescence (CL) and PL reveal a strong room temperature Z3 excitonic emission at similar to 385 nm. Electrical measurements indicate n-type conductivity with resistivity similar to 34 Omega cm. (c) 2005 Elsevier B.V. All rights reserved.