Synthesis and Analysis of Porous Silicon for Applications in Fabricating 1-D Photonic Crystals

DOI : http://dx.doi.org/10.13005/msri/040230

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Porous silicon has a great potential in photonics applications due to its tunability of refractive index by controlling the porosity of its layer during formation. Hence, the bandwidth of ?Photonic Bandgap? can be tuned by refractive index contrast of two constituent layers of porous silicon. In the present work, we have prepared porous silicon of boron doped silicon wafer with <100> orientation by vapor phase chemical etching and electrochemical etching. The ellipsometry characterization divulges the variation in refractive index of bulk silicon after pore formation of the two samples obtained to be 1.83 and 2.1. The XRD spectra reveal the shifting of intensity peak to its higher values, which confirms the existence of porous silicon. A broad peak in the spectra shows that the porous silicon has the same orientation as that of the bulk silicon and the etching process does not change its orientation. The FTIR shows the existence of strong hydrogen incorporation in porous silicon which can be minimized by annealing. The characterization of surface morphology using AFM, demonstrates the pore diameters are 70nm and 85nm of sample S1 and S2 respectively.

Porous Silicon; Photonic Crystals; Porosity; Nano-Structures