High-performance distributed feedback quantum cascade lasers grown by metalorganic vapor phase epitaxy

We report the operation of distributed feedback quantum cascade lasers, grown by metalorganic vapor phase epitaxy. Single-mode laser emission at $\lambda \sim 10.3\mu \mathrm{m}$ and $\lambda \sim 7.8\mu \mathrm{m}$ is observed from two different samples, with 300 K threshold current densities of $J_{\mathrm{th}}\sim 3$ and $\sim 2.4\mathrm{kA}{\mathrm{cm}}^{-2}$ , respectively. Structural investigation by x-ray diffraction and transmission electron microscopy, and the close correlation between the predicted and observed emission wavelengths indicate exceptional control of the layer thicknesses, including ultrathin $(\sim 8\mathrm{\AA })$ barrier layers in the active region. These results confirm metalorganic vapor phase epitaxy as a viable technology for the growth of high-performance quantum cascade lasers.