Architecting the columnar morphology of sculptured thin films for polarization-universal bandgaps

Abstract

Columnar thin films are assemblies of parallel straight columns of nanoscale cross-sectional dimensions grown by physical vapor deposition on appropriate substrates. Sculptured thin films are similar, but the columnar shape is architected for specific objectives. Polarization-universal bandgaps with maximum transmittance under 20% were realized as sculptured thin films of two different types: (i) tightly interlaced matched ambidextrous bilayers (TIMABs) to modify the circular Bragg phenomenon and (ii) equichiral sculptured thin films (ECSTFs) that display the Bragg phenomenon. The serial bideposition technique was employed for architecting the columns. Samples characterized optically as well as with scanning electron microscopy.