Hex-Ge/SiGe multiple quantum wells
We are investigating hex-Ge/SiGe quantum wells for quantum well lasers and as a first step towards hex-Ge/SiGe quantum dot single photon emitters.
(a) Schematic of a hex-Ge/SiGe multiple quantum well grown around a wurtzite GaAs core (blue). (b) Cross sectional high-resolution Transmission Electron Microscopy image of a hex-Ge/SiGe multiple quantum well. (c) Photoluminescence of a single hex-Ge/SiGe quantum well.
Observation of stimulated emission in hex-SiGe
Our research is focused towards the demonstration of a hex-SiGe nanolaser. We presently have clear proof that hex-SiGe shows strong stimulated emission.
Result showing the conversion of the spontaneous emission spectrum (black) of hex-SiGe into a stimulated emission spectrum (blue).
The stimulated emission peak increase with a slope of 2.25, as shown in the middel panel by the orange curve.
By analyzing the stimulated emission peaks with the Hakki-Paoli method, we obtain the gain spectrum as shown below. Although we observe an intrinsic loss of 2100/cm, we clearly observe a semiconductor gain spectrum above the intrinsic loss, with a maximum gain of 545/cm.
