Investigation of graded InxGa1−xP buffer by Raman scattering method

The compositional changes of InxGa1−xP graded buffer inserted between GaP substrate and subsequently grown In0.36Ga0.64P homojunction LED structure were investigated by Raman spectroscopy. The indium content of InxGa1−xP interlayers was increased in eight steps with thickness of 300 nm and constant compositional change ΔxIn between the steps. The properties of InxGa1−xP graded buffer along the structure cross-section have been studied by Raman back scattering method and the changes in GaP LO and TO phonons were investigated. Raman shift of 13 cm−1 in GaP-like LO1 phonon was measured on beveled [100][100]surface for compositional change of InxGa1−xP layer in the range of 0