Abstract

Electrically-injected group-IV light emitters have long been desired for silicon photonics. Ge is a promising material for efficient group-IV light due to the nature of qua- si-directness of band structure [1], that is, the energy difference between the direct conduct band and lowest indirect conduction band is just 136.5 meV at room temperature. While the huge lattice mismatch between Si and Ge poses challenges to directly grow Ge on Si substrates, recent advances in special growth techniques have enable the direct growth of Ge on Si substrates, and Ge-on-Si lasers have been demonstrated [2]. However, the defective interface between Ge active layer could lead to strong non-radiative recombination, likely leading to higher lasing threshold.

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