Room-temperature laser emission achieved in germanium-tin alloy

Scientists from Irig, CEA-Leti, and materials science lab C2N recently showed that a germanium-tin alloy microdisk laser cavity can emit at a record temperature of 32 °C. A tin content of 17% and a pedestal-type architecture that enables better dissipation of the heat from the stacked layers made the advance possible.
Tin atoms are larger than germanium atoms, so increasing the tin content to 17% should create crystal defects in the material. Here, the defects were prevented by a series of buffer layers with gradually increasing tin content used during epitaxial growth.
The advance marks a major step toward CMOS-compatible room-temperature laser sources.
Up next: improvements to push the device’s operating temperature even higher and improve the alloy’s crystalline quality.

Contacts: nicolas.pauc@cea.fr, vincent.calvo@cea.fr

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