Morphological analysis and photoluminescence properties of hydrophilic porous anodic alumina formed in oxalic acid

Porous anodic alumina (PAA) templates were prepared via two-step anodization process in 0.3 M oxalic acid for different anodization durations (2-10 h with a step of 2 h). In this article, we report our studies on the morphological analysis and photoluminescence (PL) properties of hydrophilic PAA templates prepared at 8 and 18 A degrees C. Two-dimensional fast Fourier transform was used to study the regularity ratio of PAA. It was found that for a longer anodization time (6, 8 and 10 h) the better array of pores observed with anodization potential of 40 V. The effect of anodization duration on the structural aspects including pore diameter, interpore distance, porosity and pore density were investigated in detail. It was observed that increase in anodization duration led to an increase in pore diameter and porosity. Contact angle measurement of PAA templates was carried out to confirm the hydrophilic nature. The relationship between morphology of PAA and PL emission bands was studied. The PL spectra of PAA templates show two emission sub-bands, which can be ascribed to two luminescence centers, F+ (band-1) and F (band-2), respectively.