The investigations of porous GaX 5 layers

Abstract

Porous GaX(5) (X(5) = As, Sb) layers produced by electrochemical etching were investigated. Chemical composition of porous layers was examined by X-ray photoelectron emission spectroscopy method (XPS), the morphology of layers was analysed by scanning electron microscope (SEM), the structure investigations were made using the electron diffraction camera and transmission electron microscope (TEM), and the photoluminescence spectra of the fabricated layers were measured in quasi-backscattering geometry. The porous samples were prepared from p-type GaAs (doped with Zn) and GaSb (Ge, Zn) (100) wafers by electrochemical etching in electrolytes containing HF. It has been shown that porous structure comprises basic (GaAs or GaSb) crystallites and transparent crystallites of Ga2O3, As2O3, As2O5 (for GaAs) and Ga2O3, Sb2O3 (for GaSb). Both 'red' (near 866 nm) and 'green' (in the spectral range of 590-690 nm) photoluminescene bands have been observed in the porous samples of GaAs and an analogous band (near 650-740 nm) was registered for GaSb layers. Some spectra dependence on etching conditions is observed. Possible origin of the observed spectra is discussed.