[en] Rare-Earth Nitrides (REN's) are quite unique in intrinsically possessing ferromagnetic and semiconducting properties simultaneously. Ferromagnetic semiconductors possess properties ideal for spintronics, where the charge and spin of the electron is used to process information. One such REN is Holmium Nitride (HoN). HoN is a promising intrinsic ferromagnetic semiconductor. Using nanocrystalline thin films grown by Ion Assisted Deposition, we have observed a direct bandgap of approximately 2.03 eV, and a Curie temperature of approximately 18 K. We have also found unusual results of rare-earth 4f electron hybridisation and a lower than expected magnetic moment per ion. We have found the growth conditions play a significant role in determining the crystal structure. I will report how the substrate temperature, growth rate, nitrogen pressure, and the nitrogen state can be optimised to improve crystal quality. I will also discuss different substrates and how they affect the crystal structure, as well as other techniques to improve the crystal quality. I will also report the first ever growth of mixed REN thin films. Specific attention will be on Dy_xHo_x-1N. The magnetism of these materials, and their crystal structure will be reported for ratios of x = 0.05, 0.25, 0.5, 0.75, and 0.95.