Light-mediated growth of chalcogenide nanostructures

Abstract

The synthesis of inorg. materials whose morphologies respond to changing illumination conditions can enable the development of complex nanostructures with tailored optical responses. We have developed a method for light-mediated pattern formation during the electrodeposition of photoresponsive selenium-tellurium (Se-Te) alloys. While no long-range structure is obsd. for Se-Te films prepd. in the dark, those deposited under illumination display a nanoscale lamellar pattern that is continuous over the entire growth substrate. We attribute the light-induced pattern formation to interference between scattered waves at the surface of the growing film, which produces a periodic modulation in the light intensity. The deposition rate of the Se-Te alloy is increased in regions of greater local intensity making the resulting patterns highly sensitive to the wavelength, polarization, and angle of the incident illumination. Further structural complexity can be built into the Se-Te nanostructures by changing the illumination conditions during the electrodeposition process.