In this paper, we present the results of structural and photoluminescence (PL) studies on porous layers produced on a heavily p-doped (100) GaAs wafer by electrochemical anodic etching. The evolution of porous GaAs structure as a function of layer preparation conditions were investigated by x-ray diffraction (XRD). We show that porous layers have the same crystallographic orientation as the substrate from which they are originated. We also report a relative XRD peak separation indicative of a variation of the lattice parameter of the porous layer. The photoluminescence of porous layers were characterized by a narrow emission band in the visible region attributed to the confinement effect in GaAs nanocrystals having a reduced size distribution. Chemical treatment in Sodium Carbonate solution was shown to enhance both the crystalline quality and the intensity ratio of visible to infrared emission of porous GaAs.
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