Strain-tuning the electronic properties of In_xGa_1-xAs (111) alloys

Strain engineering of III-V semiconductor alloys is a powerful strategy for designing nanoscale optoelectronics. This work presents a systematic first-principles investigation into the electronic properties of special quasirandom In_xGa_1-xAs (111) alloys (x = 0,1/3,2/3,1) under large biaxial strain. Using density functional theory with the HSE06 hybrid functional, we analyze how biaxial strain modifies the band gap, band alignments, and the evolution of band edges at high-symmetry k-points. Our results reveal pronounced band edge shifts, leading to direct to indirect band-gap transitions induced by strain. We quantify the valence and conduction band offsets relative to the GaAs and InAs parent compounds, identifying strain ranges where local potential wells are suitable for embedded quantum dots. These findings provide insights into designing novel heterostructures that exploit strain-induced carrier confinement in InGaAs quantum dots for advanced optoelectronic applications.