In situ photoluminescence studies of photochemically grown porous silicon

Silicon Porosification: State of the Art

“…Kolasinski et al 252 also observed the shift of PL maximum in the blue range for PSi layers, grown photochemically by irradiation with a 15 mW HeNe laser. However, this shift was smaller and observed in the range from 570 to 530 nm.…”

“…At that the profile of etching layer corresponds to a Gaussian intensity profile of the laser beam, 252 Figure 21 displays a typical film grown after exposure to a HeNe laser at normal incidence.…”

“…These processes are distinct in that they achieve three distinguishable outcomes: porous silicon formation (anisotropic photoelectrochemical etching), Profilometry studies performed out by Kolasinski et al 252 revealed that both the upper and lower interfaces of the film descend deeper into the film as etching time proceeds. However, the PSi formation rate exceeds the rate of photochemical removal, and therefore, the thickness of PSi layer increases with time.…”

“…However, this shift was smaller and observed in the range from 570 to 530 nm. Besides Kolasinski et al 252 have demonstrated that the PL spectrum obtained depends not only on the duration of irradiation but also on the wavelength of the incident light (λ fab ) used to fabricate the film (for λ fab > 473 nm). Both 365 and 473 nm light result in the same PL spectrum (within spot to spot variations) with λ peak : 550 nm.…”

Electrochemical differential photoacoustic cell to study in situ the growing process of porous materials

“…Although it has been done in situ studies of PS on n-type silicon substrates, 8,9 these studies did not reveal the intricacies of the morphology variations and their effect on the thermal and electrical properties of the composite system silicon/porous silicon ͑Si/PSi͒. In addition, Lehmann et al 10 reported the morphology of PS samples for different n-type silicon substrates with doping densities between 6 ϫ 10 16 and 2 ϫ 10 19 cm −3 range; however, PS samples on n-type silicon substrates with low doping densities and low porosities have not been extensively studied to date.…”