Superlattice Structure of Quantum Cascade Lasers: Structural and Morphological Effects of AsH₃ Flow

The quantum cascade lasers (QCLs) have been widely used in mid-infrared applications due to their high power, efficiency, and design flexibility. The InP-based quantum cascade lasers, particularly those utilizing In 0.53 Ga 0.47 As/In0.52Al0.48As superlattices, have been preferred for their lattice compatibility and well-established fabrication processes. However, the superlattice growth has required optimization, as relaxation mechanisms have affected structural quality beyond the critical thickness. In this study, InP-based quantum cascade lasers structures have been grown and characterized using Metal-Organic Vapor Phase Epitaxy (MOVPE). The impact of AsH3 (arsin) flow rate on superlattice quality has been investigated by growing samples with flow rates of 47 sccm, 60 sccm, and 75 sccm. Structural analysis has been conducted using high-resolution X-ray diffraction (HRXRD), while atomic force microscopy (AFM) has been used to examine surface morphology. The results obtained revealed the critical role of superlattice growth parameters on the performance of quantum cascade laser devices and provided important findings for determining the optimal AsH₃ flow rate. This study contributes to the improvement of growth processes of InP-based quantum cascade laser structures, leading to improved semiconductor laser performance.