Effect of InxGa1 − xAs interlayer on the properties of In0.3Ga0.7As epitaxial films grown on Si (111) substrates by molecular beam epitaxy

• We provide a simple approach to achieve high-quality In0.3Ga0.7As films on Si.
• An In0.28Ga0.72As interlayer can release mismatch strain.
• High-quality In0.3Ga0.7As film is grown on Si using 10-nm-thick interlayer.
• Smooth surface In0.3Ga0.7As film is grown on Si using 10-nm-thick interlayer.

High-quality In0.3Ga0.7As films have been epitaxially grown on Si (111) substrate by inserting an InxGa1 − xAs interlayer with various In compositions by molecular beam epitaxy. The effect of InxGa1 − xAs interlayer on the surface morphology and structural properties of In0.3Ga0.7As films is studied in detail. It reveals that In0.3Ga0.7As films grown at appropriate In composition in InxGa1 − xAs interlayer exhibit smooth surface with a surface root-mean-square roughness of 1.7 nm; while In0.3Ga0.7As films grown at different In composition of InxGa1 − xAs interlayer show poorer properties. This work demonstrates a simple but effective method to grow high-quality In0.3Ga0.7As epilayers on Si substrates, and brings up a broad prospect for the application of InGaAs-based optoelectronic devices on Si substrates.