Conventional metal patterns in integrated circuits are known to exhibit drawbacks such as signal delays and heat generation. The use of the silicon photonics technology has been proposed to overcome these drawbacks. Silicon‐based materials and processing technologies offer cost‐effective solutions for large‐scale fabrication in microelectronics, such as for the fabrication of silicon integrated circuits. However, the fabrication of light‐emitting diodes using silicon‐based materials for the silicon photonics has not been realized so far. We investigated the structural optimization of silicon to obtain a high efficiency of light emission. And we observed the correlation between the high‐efficiency light emission and alkali impurities such as Na and K.