Spectral image cathodoluminescence, photoluminescence and Raman study of GaAs layers grown on Si substrates

GaAs layers grown on Si substrates by the conformal method were investigated by means of Raman, photoluminescence and cathodoluminescence spectroscopies. The combination of these optical techniques allows a better knowledge of the properties of these layers, with special emphasis on the stress distribution and the incorporation of dopants. In particular, samples intentionally doped, with alternate doped and undoped fringes, have been analyzed. The effective incorporation of Si atoms in the GaAs structure to produce n-type layers and the formation of Si complexes are determined by Raman and cathodoluminescence data. The lateral quasi-periodic stress distribution, typically observed in these layers, is shown to affect the Si incorporation.