| Summary: | The porous layers were formed on n and p-type GaAs (100) oriented wafers, which were doped with Cr and Zn. The resulting holes concentration in bulk was equal n - 1014 cm-3 and p - 1018 cm-3.
The porous layers were formed by anodization process in different solutions such as HF:HNO3:H2O (40:1:59), HF:C2H5OH:H2O (1:1:1), (6:1:1), (15:1:1) (concentration of HF was 45%). Duration of anodization process varied from 0.5 to 60 minutes at a current density of (10 – 100) mA/cm2. After the etching, the samples were rinsed with distilled water and dried.
The analysis of surface morphology and photoluminescence of porous GaAs were given at this work. The performed observations have shown that the surface morphology strongly depends on the composition of etching solution, specific resistance of GaAs wafers, etching time and current density during the etching procedure.
A mat film is observed on the surface of electrochemically-etched GaAs. The colour of the film varied from black to light brown and to greenish. Colour variation is determined by anodization conditions determined by the composition of etching solution, current density during anodization, etching time and specific resistance of wafers. The observed films were solid. Some films were fragmented in a chaotic way or composed by oriented units.
In order to assess the luminescence properties of the porous material and their dependence on etching conditions the photoluminescence spectra of porous GaAs were measured at room... [to full text]
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