We use a simple, two-fluid model for the collective electrostatic response of a semiconductor cylindrical nanowire, which treats the electron and hole components as a two-species plasma system. An analytical expression of the dispersion relation is obtained for both surface and bulk modes by solving Poisson and hydrodynamic equations with appropriate boundary conditions. It is found that the electrostatic interaction between the fluids gives rise to splitting of the two types of modes (i.e., surface and bulk modes) into two groups. The results may be useful for understanding the collective dynamics of the nano-device semiconductor plasma.
