GeSn alloy, CMOS compatible material, has a direct electronic bandgap structure, i.e. a favorable configuration for light emission, for tin content higher than 6-8% depending of the layer strain state. Previous studies have shown that this alloy can have optical gain at cryogenic temperature by the observation of the laser regime.
We have just experimentally demonstrated the laser regime at room temperature of this material in a microdisk optical cavity thanks to the combination of an alloy richer in tin (Ge0.83Sn0.17) than previous studies, and a better heat dissipation of the layers stack by a better adapted pedestal architecture. The highest temperature of the laser regime is now 32°C, and the emission wavelength is in the mid-infrared range at 3.5µm. This result is an important milestone since it shows the potential of this CMOS compatible alloy for future applications.
8µm-GeSn microdisk on an AlN pedestal, and laser emission spectrum at 300K.
This work was carried out in collaboration with the CEA-LETI (Grenoble) and the C2N (Paris-Saclay) within the framework of the ANR ELEGANTE.
Contacts:
Vincent Calvo and
Nicolas Pauc