Raman spectroscopy for characterizing compositional intermixing in GaAs AlGaAs heterostructures

Compositional intermixing induced by the process of impurity-free vacancy ( dielectric cap annealing induced) disordering in GaAs/AlGaAs is studied usi ng Raman spectroscopy. The degree of intermixing in multiple-quantum-well s tructures was detected through the energy shift of certain Raman modes of t he lattices. In addition, localized intermixing, with band-gap shifts as lo w as 6 nm realized in 1:1 band-gap grating patterns with different periods (greater than or equal to 4 mu m), was also detected through the energy shi ft and the full width at half maximum of the structures's Raman modes. (C) 1999 American Institute of Physics. [S0003-6951(99)01226-7].