Revealing stacking sequences in inverse opals by microradian X-ray diffraction

Abstract

-We present the results of the structural analysis of inverse opal photonic crystals by microradian X-ray diffraction. Inverse opals based on different oxide materials (TiO2, SiO2 and Fe2O3) were fabricated by templating polystyrene colloidal crystal films grown by the vertical deposition technique. Our results suggest that most inverse opal films possess dominating twinned face-centered cubic structure accompanied by some fragments of hexagonal close-packed and random hexagonal close-packed structures. The studied samples possessed individual structures with different ratios of the above fragments. By fitting the results of the angular-dependent X-ray diffraction by the Wilson model we estimate the stacking probability α in the studied samples to be ∼0.7-0.8. Microradian X-ray diffraction therefore provides detailed structural information on opal-based photonic crystals and can be applied to opaque inverse opals or the samples with a periodicity < 300 nm, whose structure cannot be investigated by conventional optical methods.

Large-scale ZnO inverse opal films fabricated by a sol–gel technique

“…Thus, sol-gel synthesized ZnO inverse opals do not undergo a severe structural degradation and have structural quality comparable to that of colloidal crystal templates. In order to further investigate the crystalline quality of ZnO inverse opals on a macroscale, the samples were studied by microradian X-ray diffraction [23,24]. Fig.…”

Periodic order and defects in Ni-based inverse opal-like crystals on the mesoscopic and atomic scale

“…4(a) with dark circles. According to our previous papers [5,11,[17][18][19][20], these rods can be related either to the finite thickness of the colloidal crystal or to increased amount of planar defects and mechanical stress in the crystal. Apart from this, the paper [21] demonstrates surface truncation to be a probable reason for the appearance of the rods.…”

“…Another interpretation is still to consider such a structure as fcc, while with a considerable amount of stacking faults [16]. Also, our previous works [5,11,[17][18][19][20] on this issue demonstrated effectiveness of the mesostructure determination using small-angle neutron and synchrotron diffraction.…”

Исследование Квазидвумерных И Квазитрехмерных Упорядоченных Пористых Структур Методами Малоугловой Дифракции В Скользящей Геометрии

“…Вопросы изменения физических свойств пленочных образцов опалоподобных структур при переходе из 2М-в 3М-измерение уже обсуждались нами в ста-тьях [35][36][37] при анализе данных, полученных метода-ми ультрамалоуглового рассеяния синхротронного из-лучения и SQUID-магнетометрии. В работах [38,39] освещены теоретические и экспериментальные вопросы исследования двумерных и трехмерных опалоподобных фотонных структур с помощью оптических методов.…”