Presently, the manufacturing technology of silicon-based light sources that are compatible with complementary metal oxide semiconductor processes and have high luminous efficiency is immature. To address this problem, a new structure for a poly-silicon light-emitting device is proposed in this paper. The possible avalanche modes (interband transition, bremsstrahlung, intraband transition of holes between light and heavy mass bands, ionization under high-field conditions, and indirect interband reorganization) of the device under reverse bias voltage are studied. The mechanism is analyzed theoretically; moreover, the drift and diffusion of holes and electrons inside the device under reverse bias voltage are studied, which reveals that carrier injection increases the number of carriers involved in the avalanche multiplication process and can lead to an increase in the impact ionization rate. Furthermore, the electric field, spectrum, current, and light intensity of the device are analyzed. The quantum efficiency and photoelectric conversion efficiency are calculated; it is concluded that the impact ionization rate is improved by the carrier injection. The improvement in the device''s luminous efficiency is achieved by the improvement in the impact ionization rate, for which the quantum efficiency is 5.9×10 -5 and photoelectric conversion efficiency is 4.3×10 -6.