@ARTICLE{10.3389/fmats.2014.00015, AUTHOR={Saito, Shinichi and Gardes, Frederic Yannick and Al-Attili, Abdelrahman Zaher and Tani, Kazuki and Oda, Katsuya and Suwa, Yuji and Ido, Tatemi and Ishikawa, Yasuhiko and Kako, Satoshi and Iwamoto, Satoshi and Arakawa, Yasuhiko}, TITLE={Group IV Light Sources to Enable the Convergence of Photonics and Electronics}, JOURNAL={Frontiers in Materials}, VOLUME={1}, YEAR={2014}, URL={https://www.frontiersin.org/articles/10.3389/fmats.2014.00015}, DOI={10.3389/fmats.2014.00015}, ISSN={2296-8016}, ABSTRACT={Group IV lasers are expected to revolutionize chip-to-chip optical communications in terms of cost, scalability, yield, and compatibility to the existing infrastructure of silicon industries for mass production. Here, we review the current state-of-the-art developments of silicon and germanium light sources toward monolithic integration. Quantum confinement of electrons and holes in nanostructures has been the primary route for light emission from silicon, and we can use advanced silicon technologies using top-down patterning processes to fabricate these nanostructures, including fin-type vertical multiple-quantum-wells. Moreover, the electromagnetic environment can also be manipulated in a photonic crystal nanocavity to enhance the efficiency of light extraction and emission by the Purcell effect. Germanium is also widely investigated as an active material in Group IV photonics, and novel epitaxial growth technologies are being developed to make a high quality germanium layer on a silicon substrate. To develop a practical germanium laser, various technologies are employed for tensile-stress engineering and high electron doping to compensate the indirect valleys in the conduction band. These challenges are aiming to contribute toward the convergence of electronics and photonics on a silicon chip.} }