Low field electron emission from novel carbon based cold cathodes is reported. The cathodes consisted of a layer of nanoseeded diamond and an over layer of nanocluster carbon films. The nanoseeded diamond was first coated on to thesubstrate. The nanocluster carbon films were then deposited on the nanocrystalline diamond coated substrates using the cathodic arc process at room temperature. The heterostructured microcathodes were observed to exhibit electron emission currents of 1 $mu$A/cm$^2$ at fields as low as 1.5 to 2V/$mu$m. The effect of the nanoseeded diamond size and concentration and the properties of different nanocluster carbon films on emission characteristics is presented.