High power short mid-infrared quantum cascade lasers based on ultrathin AlAs intercalation layers grown by MOCVD

Quantum cascade lasers (QCLs) are promising light sources for the mid-to-far-infrared spectral region. Their performances have made great improvements with realizing room temperature high power continuous wave (CW) operation for different wavelengths. Nevertheless, limited by poor material quality or serious electron thermal leakage, efficient lasing for the short mid-infrared range, that is, shorter than 4 μm, is still challenging. Here, the design with ultrathin AlAs intercalations to the InAlAs barriers based on standard In 0.7 Ga 0.3 As / In 0.36 Al 0.64 As materials for short mid-infrared QCLs is demonstrated. The introduction of ultrathin AlAs intercalated layers raises the positions of the parasitic levels, which efficiently suppresses electron thermal leakage, and higher device performances are expected. Meanwhile, due to the small thickness of the AlAs intercalated layers, the material growth is similar to the standard growth process for 4−5 μm QCLs. Therefore, high quality material epitaxy is easy and feasible for metal organic chemical vapor deposition (MOCVD). QCLs grown by MOCVD emitting at 3.57 μm, 3.88 μm, and 4.05 μm are demonstrated, which exhibit significant performance improvement compared with previously reported devices grown by MOCVD for similar wavelengths. Considering the advantages of high throughput, efficiency, and low costs of MOCVD, our study provides a convenient and efficient approach for high power short mid-infrared QCLs.