Abstract
The influence of structural configurations of indium aluminum nitride (InAlN) nanospirals, grown by reactive magnetron sputter epitaxy, on the transformation of light polarization are investigated in terms of varying structural chirality, growth temperatures, titanium nitride (TiN) seed (buffer) layer thickness, nanospiral thickness, and pitch. The handedness of reflected circularly polarized light in the ultraviolet–visible region corresponding to the chirality of nanospirals is demonstrated. A high degree of circular polarization (Pc) value of 0.75 is obtained from a sample consisting of 1.2 μm InAlN nanospirals grown at 650 °C. A film-like structure is formed at temperatures lower than 450 °C. At growth temperatures higher than 750 °C, less than 0.1 In-content is incorporated into the InAlN nanospirals. Both cases reveal very low Pc. A red shift of wavelength at Pc peak is found with increasing nanospiral pitch in the range of 200–300 nm. The Pc decreases to 0.37 for two-turn nanospirals with total length of 0.7 μm, attributed to insufficient constructive interference. A branch-like structure appears on the surface when the nanospirals are grown longer than 1.2 μm, which yields a low Pc around 0.5, caused by the excessive scattering of incident light.
Highlights
Chirality-induced polarization effect in the cuticle of scarab beetles, such as Cetonia aurata and Chrysina argenteola, is well-known to reflect light with brilliant color and a high degree of circular polarization [1,2,3]
Efforts have been devoted to the fabrication and exploration of various chiral structures and materials by methods including glancing angle deposition (GLAD) [8,9], direct laser writing (DLW) [10,11], and holographic lithography (HL) [12]
The SEM and X-ray diffraction (XRD) results indicate that these indium aluminum nitride (InAlN) chiral nanospirals grow preferentially along the c-axis and have the same In content of 0.19, as calculated by Vegard’s law without taking strain effect into consideration [23]
Summary
Chirality-induced polarization effect in the cuticle of scarab beetles, such as Cetonia aurata and Chrysina argenteola, is well-known to reflect light with brilliant color and a high degree of circular polarization [1,2,3]. Different materials can be used to fabricate chiral structures for such polarization-sensitive optical materials, including oxides and fluorides [13,14], gold [11], liquid crystals [15], and silicon nitride [16].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
