Pressure‐induced resonance Raman scattering in Ga1−xInxAs/Ga1−yAlyAs strained quantum‐well structures

Pressure‐tuned resonance Raman scattering (RRS) experiments in Ga1−xInxAs/Ga1−yAlyAs strained‐layer quantum‐well samples with x=0.15 and y=0.15, on a GaAs substrate, are reported. The photoluminescence (PL), 2LO‐, and LO‐phonon Raman‐scattered intensities were followed as a function of pressure using the diamond cell. In backscattering geometry and with (100) samples, three sharply defined 2LO‐phonon resonances are observed, at 2.1, 3.8, and 5.2 GPa, with 647.1‐nm excitation (ℏωL=1.916 eV), and these are identified to be from the AlGaAs, GaAs, and InGaAs layers, respectively. At the above pressures, the 2LO peak of the layer falls right on top of the PL peak of the corresponding layer, revealing that the resonance occurs when E0=ℏωS (2LO). For the LO‐phonon intensity, maxima are observed at 2.8 and 4.7 GPa, respectively, from the AlGaAs layer and GaAs substrate. While the LO‐resonance profile (pressure versus phonon intensity) for the AlGaAs layer is narrow, the profile of the GaAs substrate layer is high...