Nanoscale heterostructures, which incorporate two or more materials such as core-shell nanocrystals, core-crown nanoplates, or seeded nanorods, allow better control of the optical, electrical and magnetic properties that are inaccessible in single component nanostructure, yet their variety and controlled growth are still challenging. Here, a nail-like Mn-doped CdS/CdBr2 hetero-nanostructure, which has a hexagonal plate on top of a nanowire, is firstly fabricated by a simple one-step thermal evaporation process. According to the characterization results, its growth mechanism could be obtained, in which the manganese bromide precursor plays a critical role in the formation of such nail morphology. The amplified spontaneous emission of the 'nanonail' is achieved at a low threshold at room temperature, which come from the local and dense exciton scattering due to their interactions excited by fs pulse. These interesting nail-like heterostructures may provide promising templates for constructing high-performance optoelectronic devices.