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Long-wavelength InAs/GaAs quantum-dot laser diode monolithically grown on Ge substrate



The realization of semiconductor laser diodes on Si substrates would permit the creation of complex optoelectronic circuits, enabling chip-to-chip and system-to-system optical communications. Direct epitaxial growth of IIIV semiconductor materials on Si or Ge is one of the most promising candidates for the fabrication of electrically pumped light sources on a Si platform. Here, we describe the first quantum-dot laser to be realized on a Ge substrate. To fabricate the laser, a single-domain GaAs buffer layer was first grown on the Ge substrate using the Ga prelayer technique. A long-wavelength InAs/GaAs quantum-dot structure was then fabricated on the high-quality GaAs buffer layer. Lasing at a wavelength of 1,305 nm with a low threshold current density of 55.2 A cm–2 was observed under continuous-wave current drive at room temperature. The results suggest that long-wavelength InAs/GaAs quantum-dot lasers on Si substrates may be realized by epitaxial growth on Ge-on-Si substrates.

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Figure 1: Structural properties of GaAs buffer layer on Ge substrate.
Figure 2: InAs QD laser diode on a Ge substrate.
Figure 3: Room-temperature emission spectra, light output power and electrical characteristics.
Figure 4: Temperature-dependent light output power characteristics.


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The authors acknowledge funding support from the Royal Society and the Defense Science Technology Laboratory.

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Authors and Affiliations



H.L. and A.S. proposed and guided the overall project. H.L., T.W. and F.T. developed and performed material growth and characterization. T.W., Q.J., R.H., F.P. and A.S. were involved with device design, fabrication, measurement and assessment. All authors assisted with preparation of the manuscript and discussed the results.

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Correspondence to Huiyun Liu.

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The authors declare no competing financial interests.

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Liu, H., Wang, T., Jiang, Q. et al. Long-wavelength InAs/GaAs quantum-dot laser diode monolithically grown on Ge substrate. Nature Photon 5, 416–419 (2011).

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