We here demonstrate the use of semiconductor chalcogenide nanocrystals as single-source precursors for the one-step formation of flexible functional films. By taking advantage of the surface chemistry of these “zero-dimensional” building blocks we obtain close-packed three-dimensional arrays of nanocrystals interconnected by oxide sheaths. The films are obtained by exposing oxidation-resistant nanocrystals to an air plasma treatment. This treatment does not significantly influence the photoluminescence efficiency of the individual nanocrystal building blocks but confers them resilience to bending as well as resistance to acidic environments, hot solvents, annealing, and UV irradiation.

We report on the observation of resonant Zener tunnelling of light waves in an optical superlattice. The one dimensional (1D) structures are made in free-standing porous silicon and are designed specifically to exhibit two photonic minibands. A controlled optical path gradient has been maintained over the sample thickness which resulted in tilting of photonic minibands and formation of optical Wannier-Stark ladders. At a certain value of optical gradient the two minibands couple within the extension of the structure and a resonant tunnelling channel through the superlattice forms, resulting in a very high transmission peak. Ultrafast time resolved transmission experiments were performed: excitation of the Wannier-Stark states causes the appearance of photonic Bloch oscillations, which are strongly damped when Zener tunneling modes are excited. The observed phenomenon is the optical analogue of resonant Zener tunnelling in an electronic superlattice.