The authors propose a Ge/Ge 0.76Si 0.19Sn 0.05 quantum cascade laser using intersubband transitions at L valleys of the conduction band which has a "clean" offset of 150 meV situated below other energy valleys (Γ, X). The entire structure is strain-free because the lattice-matched Ge and Ge 0.76Si 0.19Sn 0.05 layers are to be grown on a relaxed Ge buffer layer on a Si substrate. Longer lifetimes due to the weaker scattering of nonpolar optical phonons reduce the threshold current and potentially lead to room temperature operation.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)