Plasmonic nano-cavity laser based on a III-V semiconductor nano-ring on silicon can operate either in in-plane dipole mode or vertical coaxial mode. This paper gives the simulation, design and some fabrication discussions of this unique nano-cavity laser. Body-of-revolution ¯nite-di®erence-time-domain (BOR-FDTD) is used for the modal analysis and design of cavity. The spatial and temporal lasing performance of this nano-cavity laser is simulated incorporating the BOR-FDTD with multilevel gain medium model. Comparison between these two lasing modes is presented and numerical analysis shows that the in-plane dipole mode can achieve the smallest mode volume reported so far. Fabrication of this semiconductor plasmonic nano-cavity laser is discussed.This semiconductor plasmonic nano-cavity laser has a deep sub-wavelength foot-
print and ultralow power consumption, which can act as an on-chip light source for intrachip data interconnect.