Gallium-nitride nano-column arrays were grown on a platinum-coated Si(111) substrate by using the Pt+GaN alloy seeding method with metal-organic chemical vapor deposition (MOCVD). Two important growth parameters were considered, the pre-deposition of the Ga source prior to generating the droplets and the droplet formation temperature. The surface morphology and the optical characterization of the grown GaN nano-columns were studied using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence (PL). The SEM image reveals the vertical growth of GaN nano-columns. The growth of the GaN nano-columns was confirmed by EDX, which indicated that they were composed of gallium and nitrogen. The PL spectrum reveal a sharp peak at 366.7 nm with a full width at half maximum (FWHM) of 160 meV, which clearly indicated that the grown GaN nano-columns were highly crystalline in nature.