Grazing-Incident X-ray Diffraction (GIXRD/2θ-scan)
Grazing-Incident X-ray Diffraction (GIXRD), is a powerful analytical technique used to investigate the crystal structure of materials, with a particular focus on their surface properties. Employing X-rays at a low incident angle, often near the critical angle for total external reflection, GIXRD enhances sensitivity to the near-surface region of materials. This makes it an invaluable tool for studying thin films, interfaces, and surface layers. The 2θ-scan configuration, where the detector is positioned at twice the incident angle, allows for precise analysis of diffraction patterns, offering detailed insights into crystallographic orientation, strain, and texture.
GIXRD/2θ-scan plays a pivotal role in materials science, offering a comprehensive understanding of the structural characteristics that significantly influence the behavior and functionality of diverse materials. This method is instrumental in uncovering surface phenomena and crystallographic features, contributing to advancements in fields ranging from semiconductor technology to catalysis research. Explore the capabilities of GIXRD/2θ-scan to unlock a wealth of knowledge about material surfaces, enabling researchers to tailor materials with enhanced properties for various applications.
Interfacial engineering and film-forming study
Fig. 1a outlines the fabrication process for PSCs using PEDOT:PSS or PEDOT:PSS-GO:NH3 composite films. Figs. 1b and 1d display 2D-GIXRD images of CH3NH3PbI3-xClx films on different interfaces. Bright, spotty diffraction rings confirm textured crystal domains on all HTLs, with prominent (110), (220), and (310) peaks. Notably, ITO/PEDOT:PSS-GO:NH3 exhibits superior perovskite crystallization, with sharper and brighter peaks compared to other substrates (Fig. 1e). This suggests highly ordered perovskite structure formation, particularly on PEDOT:PSS-GO:NH3 substrates.
Reference:
Y. Yang, L. Yang, S. Feng. Interfacial engineering and film-forming mechanism of perovskite films revealed by synchrotron-based GIXRD at SSRF for high-performance solar cells. Materials Today Advances 2020, 6, 100068.
https:// www.sciencedirect.com/science/article/pii/S2590049820300151
Substrate strain study
In this study, GIXRD patterns of irradiated W at various incident angles (0.1º to 10º) are shown in Figure 2a. The key diffraction peaks, identified as (110), (200), (211), and (220) of the body-centered cubic structure, are displayed. The (110) peaks, magnified in Figure 2b–d, shift to lower 2θ angles with increased incident angles, revealing irradiation-induced lattice swelling. The zigzag patterns in the diffraction peaks of irradiated samples suggest a non-uniform distribution of (110) interplanar spacing. Consequently, analyzing these GIXRD data at different incident angles is imperative for investigating the microstructure evolution following ion irradiation, including compressive strain and expansion strain.
Reference:
Huang W, Sun M, Wen W, Yang J, Xie Z, Liu R, Wang X, Wu X, Fang Q, Liu C. Strain Profile in the Subsurface of He-IonIrradiated Tungsten Accessed by S-GIXRD. Crystals 2022, 12, 691.
https://doi.org/10.3390/cryst12050691
Investigate oxide composition
In this research, GIXRD showcased its efficacy as a rapid and straightforward tool for quantitatively investigating the composition of amorphous mixed oxides, specifically combining Ta2O5 with varying percentages of SiO2. Figure 3 illustrates a series of GIXRD diffractograms for Ta2O5/SiO2 mixed layers in the 2θ angular range of 5 to 42 degrees. These were obtained under two experimental conditions: (a) with a 0.6 mm slit width and (b) with a 2.0 mm slit width for both input and output beams. Employing a peak-fit analysis, the observed correlation was quantified, resulting in interpolation functions. These functions serve as calibration curves, facilitating the accurate determination of film composition, as depicted in Figures 3c and 3d.
Reference:
Achilli, E.; Annoni, F.; Armani, N.; Patrini, M.; Cornelli, M.; Celada, L.; Micali, M.; Terrasi, A.; Ghigna, P.; Timò, G . Capabilities of Grazing Incidence X-ray Diffraction in the Investigation of Amorphous Mixed Oxides with Variable Composition. Materials 2022, 15, 2144.
https://doi.org/10.3390/ma15062144