Photoluminescence and raman studies of an in _xGa _1-xP quantum wire structure fabricated using lateral composition modulation

We report polarized photoluminescence (PL) and Raman scattering from In _xGa _1-xP quantum wire (QWR) and lateral superlattice structures grown using the lateral composition modulation (LCM) that is formed during the growth of InP/GaP short-period superlattices (SPSs). The QWR structure was fabricated in the presence of LCM by reducing the growth thickness of the SPS layers. Strong anisotropies between the PL responses polarized parallel and perpendicular to the elongated direction of LCM were observed both in the lateral superlattice and in the QWR structure. By comparing PL spectra taken at T = 10 K and 300 K, we identified the origin of each PL peak. Raman spectra revealed that a GaP-like longitudinal optical mode in the QWR structure displayed an energy shift of 2 cm ^-1 and a broadening of the linewidth compared to that in the lateral superlattice. The energy shift is presumably related to a difference in strain and/or an increase in CuPt-type ordering. An increase in the strain variations in the QWR structure is responsible for the broadening of the linewidth.