Zinc phosphide (Zn 3P 2) thin films have been deposited by plasma assisted vapor phase deposition at substrate temperatures of 200–500°C. All the as-grown Zn 3P 2 films indicate p-type conductivity. Optical study shows that the films have 1.5 eV direct bandgap at room temperature. The Zn 3P 2 films grown at a DC bias of -500 V on glass substrates have a strongly preferred orientation in the [004] direction. The DC bias applied during growth has improved the crystallinity and grain size of the films, which contributed to reduce leakage current in ITO/Zn 3P 2 and Mg/Zn 3P 2 devices.