Dynamic and Photoluminescence Behavior of Nanocrystallites and Bulk Porous Silicon Texture

The silicon wafer with golden illuminating nanoporous thin film was obtained by anodizing boron doped silicon wafers by provided appropriate electric input of 20 mA/cm² through Keithley source meter. An increase in anodization time shifts the photoluminescence (PL) spectra to a higher PL emission energy as well as a higher PL emission intensity. The dynamic properties of the photoluminating porous silicon thin film were analyzed for the sample obtained at different etching times. Upon excitation at 410 nm, the photoluminescence exhibited a single-exponential decay signal and the decay time doesn’t depend on the etching time. Small differences in decay time at each spot on the etched surface of the same sample show the distribution dependence of nanocrystallite size. Images of the sample fluorescence also show a distribution in brightness. This complex behavior provides evidence that the quantum confinement effect could be playing an important role.