The results of Raman, photoluminescence and double-crystal X-ray diffraction measurements of GaAs films on Si substrates showed that the dislocation density was equal to about 107/cm2, and that the strain was about 0.001. The results demonstrated that GaAs/Ge/Si heterostructures that had been grown by using the 2-step method exhibited superior crystallinity. It was concluded that an improvement in the optical properties was due to a reduction in the dislocation density, of the GaAs buffer, which resulted from heat treatment during the initial stages of growth of the GaAs active layer.

Y.D.Woo, H.I.Lee, T.W.Kang, T.W.Kim, K.L.Wang: Journal of Materials Science Letters, 1995, 14[19], 1340-3