Oscillations of light absorption in 2D macroporous silicon structures with surface nanocoatings

We investigated the near-IR light absorption oscillations in 2D macroporous silicon structures with microporous silicon layers and CdTe, ZnO surface nanocrystals. The electro-optical effect was taken into account within the strong electric field approximation. Well-separated oscillations were observed in the spectral ranges of the surface bonds of macroporous silicon structures with surface nanocrystals. The model of the resonant electron scattering on impurity states in electric field of heterojunction “silicon-nanocoating” on macropore surface as well as realization of Wannier-Stark effect on the randomly distributed surface bonds were considered. The Wannier-Stark ladders are not broken by impurities because of the longer scattering lifetime as compared with the period of electron oscillations in an external electric field, in all spectral regions considered for macroporous silicon structures with CdTe and ZnO surface nanocrystals.

Research highlights▶ We observed the well-separated light absorption oscillations in the spectral ranges of the surface bonds of 2D macroporous silicon structures with microporous silicon layers and CdTe, ZnO surface nanocrystals. ▶ The model of the resonant electron scattering on impurity states in electric field of heterojunction “silicon-nanocoating” on macropore surface and realization of Wannier-Stark effect were considered. ▶ The Wannier-Stark ladders are not broken by impurities due to the longer scattering lifetime as compared with the electron oscillation period.