Influence Of Anodization Temperature On Geometrical And Optical Properties Of Porous Anodic Alumina(Paa)-Based Photonic Structures

In this work, the influence of a wide range anodizing temperature (5-30 degrees C) on the growth and optical properties of PAA-based distributed Bragg reflector (DBR) was studied. It was demonstrated that above 10 degrees C both structural and photonic properties of the DBRs strongly deteriorates: the photonic stop bands (PSBs) decay, broaden, and split, which is accompanied by the red shift of the PSBs. However, at 30 degrees C, new bands in transmission spectra appear including one strong and symmetric peak in the mid-infrared (MIR) spectral region. The PSB in the MIR region is further improved by a small modification of the pulse sequence which smoothen and sharpen the interfaces between consecutive low and high refractive index layers. This is a first report on PAA-based DBR with a good quality PSB in MIR. Moreover, it was shown that in designing good quality DBRs a steady current recovery after subsequent application of high potential (U-H) pulses is more important than large contrast between low and high potential pulses (U-H-U(L)contrast). Smaller U-H-U(L)contrast helps to better control the current evolution during pulse anodization. Furthermore, the lower PSB intensity owing to the smaller U-H-U(L)contrast can be partially compensated by the higher anodizing temperature.