Epitaxial InGaAs Films Directly Grown on Si(001) for 1.5 μm Light Emission

The integration of III–V optoelectronic materials on Si substrates is essential for advancing high-performance on-chip optical communication systems. While GaAs has been successfully grown on Si, achieving high-quality ternary III–V semiconductors such as InGaAs on Si remains challenging due to significant lattice mismatches and complex elemental compositions. In this study, we developed epitaxial In0.25Ga0.75As films directly grown on Si using molecular beam epitaxy (MBE) for long-wavelength light emission from InAs quantum dots (QDs). To enhance the crystalline quality of the In0.25Ga0.75As layers, we utilized a Si substrate patterned with Si(111)-faceted structures and incorporated InGaAs/InAlAs dislocation filter layers (DFLs). Room-temperature light emission from InAs QDs on In0.25Ga0.75As/Si at approximately 1.5 μm was achieved, with the emission wavelength tunable by adjusting the indium content in the InGaAs buffer layer. Compared to conventional step-graded InxGa1–xAs buffers on GaAs/Si templates, the InGaAs/Si film is thinner, which effectively reduces cracking issues. These results pave the way for the development of InGaAs-based laser sources on Si, thereby advancing integrated photonic devices and high-performance optical communication technologies.