Porous GaAs formed by a two-step anodization process

In this letter, we proposed a method in which a n-type GsAs wafer was first anodized in HF for a short time to form a high density of etch pits on its surface and then anodized in KOH solution to form a high density of pores with uniform distribution in it. Scanning electron microscopy revealed feature sizes of the porous structure in the nanometer range. The porous GaAs has been investigated using double crystal X-ray diffraction technique. Crystal quality and crystallographic orientation of the porous layer were similar to those of the substrate. The lattice constant of porous layer is slightly larger than that of the substrate in the growth direction.