TILTED SUPERLATTICE COMPOSITION PROFILE MEASURED BY PHOTOLUMINESCENCEAND RAMAN

The composition profile of an (AlAs)1/2(GaAs)1/2 tilted superlattice w as determined to be sinusoidal, varying from Al0.4Ga0.6As to Al0.6Ga0. 4As. The energy and polarization of the direct and indirect band gap p hotoluminescence were examined before and after thermally induced diso rdering. The shift of the direct band gap photoluminescence peak was m easured as a function of layer interdiffusion and compared to a theore tical model to find the composition profile. Raman spectroscopy was us ed to measure the linewidths of the tilted superlattice longitudinal o ptic phonons. These linewidths were compared to those from a uniform a lloy and a conventional superlattice. The data support the assignment of a sinusoidal composition profile to the tilted superlattice.