Guzzi, M.Grilli, E.Oggioni, S.Staehli, J. L.Bosio, C.Pavesi, L.2007-08-312007-08-312007-08-31199210.1103/PhysRevB.45.10951https://infoscience.epfl.ch/handle/20.500.14299/11053WOS:A1992HU79900013The energy of the indirect X exciton in AlxGa1-xAs epitaxial layers (with 0.38 < x < 0.81) has been determined by photoluminescence measurements at a sample temperature of 12 K; from these data, the dependence on the Al concentration x of the energy of the GAMMA-X gap has been obtained: E(g)X(x) = 1.988 + 0.207x + 0.055x2 eV. This relation is characterized by a very small bowing. From our data we deduce also the coordinates of the GAMMA-X crossover point: x(c) = 0.385 +/- 0.016 and E(c) = 2076 +/- 4 meV at T = 0 K and x(c) = 0.396 +/- 0.016 and E(c) = 1997 +/- 4 meV at T = 300 K.CONDUCTION-BAND MINIMASEMICONDUCTOR ALLOYSGA1-XALXAS ALLOYSPHOTOLUMINESCENCEEDGEtext::journal::journal article::research article