Monolithically Integrated Ge-on-Si Active Photonics

Article English OPEN
Jifeng Liu (2014)
  • Publisher: MDPI AG
  • Journal: Photonics (issn: 2304-6732)
  • Related identifiers: doi: 10.3390/photonics1030162
  • Subject: integrated silicon photonics | GeSi | TA1501-1820 | GeSn | band engineering | lasers | photodetectors | Applied optics. Photonics | tensile strain | modulators | optoelectronics | Ge
    arxiv: Condensed Matter::Materials Science | Physics::Optics

Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS) processing. In this paper, we present a review of the recent progress in Ge-on-Si active photonics materials and devices for photon detection, modulation, and generation. We first discuss the band engineering of Ge using tensile strain, n-type doping, Sn alloying, and separate confinement of Γ vs. L electrons in quantum well (QW) structures to transform the material towards a direct band gap semiconductor for enhancing optoelectronic properties. We then give a brief overview of epitaxial Ge-on-Si materials growth, followed by a summary of recent investigations towards low-temperature, direct growth of high crystallinity Ge and GeSn alloys on dielectric layers for 3D photonic integration. Finally, we review the most recent studies on waveguide-integrated Ge-on-Si photodetectors (PDs), electroabsorption modulators (EAMs), and laser diodes (LDs), and suggest possible future research directions for large-scale monolithic electronic-photonic integrated circuits on a Si platform.
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