Résumé
Type-II quantum well (QW) interband cascade lasers (ICLs) have emerged as the most efficient laser sources in the mid-infrared (MIR) spectral range, especially between 3 and 6 µm. However, their widespread adoption in commercial applications, such as trace gas detection and industrial process monitoring, is hindered by the use of small, expensive native substrates. A promising solution lies in the growth of ICLs on cost-effective, large-sized mismatched substrates like Si or GaAs. This approach could significantly reduce production costs while enabling the integration of high-performance MIR lasers and photonic sensors with silicon-based photonic integrated circuits (PICs).
We have successfully demonstrated the fabrication of ICLs emitting in the 3 -5 µm range, grown on both GaAs and Si substrates. Despite the presence of high threading dislocation densities, all devices exhibited performance comparable to those grown on native substrates and showed long device lifetimes. These results suggest that the active region designs based on type-II QWs may possess an inherent tolerance to dislocations, an important advantage for developing low-cost ICLs and enabling the fabrication of optical gas sensors on Si PICs.