NSRRC Activity Report 2023

062 NSRRC ACTIVITY REPORT 2023 TLS 24A1 XPS, UPS, XAS, APXPS • XPS, UPS • Materials Science, Batteries, Catalysts References 1. N. T. Temesgen, H. K. Bezabh, M. A. Weret, K. N. Shitaw, Y. Nikodimos, B. W. Taklu, K. Lakshmanan, S. C. Yang, S. K. Jiang, C. J. Huang, S.-H. Wu., W.-N. Su., B. J. Hwang, J. Power Sources 556 , 232462 (2023). 2. G. B. Berhe, W.-N. Su, T. T. Hagos, H. K. Bezabh, T. M. Hagos, B. J. Hwang, J. Power Sources 558 , 232567 (2023). 3. B. W. Taklu, Y. Nikodimos, H. K. Bezabh, K. Lakshman- an, T. M. Hagos, T. A. Nigatu, S. K. Merso, H.-Y. Sung, S.-C. Yang, S.-H. Wu, W.-N. Su., B. J. Hwang, Nano Energy 112 , 108471 (2023). 4. H. K. Bezabh, J.-C. Chiou, T. A. Nigatu, T. M. Hagos, S.-K. Jiang, Y. Nikodimos, B. W. Taklu, M.-C. Tsai, W.-N. Su, B. J. Hwang, ACS Appl. Mater. Interfaces 15 , 7949 (2023). 5. S. N. Afraj, C. H. Kuan, J. S. Lin, J. S. Ni, A. Velusamy, M. C. Chen, E. W. G. Diau, Adv. Funct. Mater. 33 , 2213939 (2023). Hold the Sun in the Palm of Your Hand Microbeam GIWAXS is used in the study of solar cells. A thin film is a layer of material deposited or coated on substrates with a thickness in the range of nanometers to a few micrometers. X-ray scattering methods are frequently used for thin film analysis. Due to the thickness of thin films and the existence of substrates, the transmission geometry of small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS) is limited. Therefore, grazing-incidence small-angle X-ray scattering (GISAXS) and grazing-incidence wide-angle X-ray scattering (GIWAXS) are extensively applied in thin film structural analysis. In the geometry of grazing incidence, an X-ray beam impinges on the surface of a thin film with an angle close to the total reflection angle, thereby increasing the penetration path in the sample. In-plane and out-of-plane structures of thin film are extracted from X-ray scattering patterns that are collected by two-dimensional X-ray detectors. TPS 25A is capable of performing transmission and grazing-incident SAXS/WAXS. The total X-ray photon flux at the sample position is approximately 10 12 photons/second and the vertical and horizontal beam sizes at the sample position are approximately 3 and 5–10 μm, respectively. With the typical incident angle ( i.e. , 0.05°), the footprint on the thin film is about 5 mm. The sample stage is composed of a hexapod and a stand for thin films. The six-axis positioning system provides with submicron precision and rigid stability. For scattering pattern collection, the instrument is equipped with two area X-ray detectors, a Dectris EIGER X 1M and 16M. The 16-megapixel detector is for SAXS/GISAXS and the smaller, 1-megapixel detector is for WAXS/GIWAXS. With the incident X-ray photon energies in the range of 5.4 to 20 keV, the q-range with the small-angle detector covers 0.0007 to 0.7 Å -1 . An order-of-magnitude of two in the q-range can be achieved in one acquisition. For wide-angle experiments, the q value is up to 5 Å -1 . For an isotropic SAXS sample, the magnitude of the momentum transfer can be expressed as: where 2θ is the scattering angle and λ is the wavelength ofthe incident X-ray. In grazing-incidence geometry, the vector components must be taken into account: where x, y, and z are the in-plane direction, beam direction, and out-of-plane direction, respectively, α i is the incident angle, α f is the out-of-plane scattering angle, and 2θ f is the in-plane scattering angle. q = — sin ( — ) 4 π λ 2 θ 2 q x = — [ cos s ( α f ) cos cos (2 θ f ) - cos cos ( α i ) ] 2 π λ q y = — cos cos ( α f ) sin sin (2 θ f ) 2 π λ q z = — [ sin sin ( α f ) sin sin ( α i ) ] 2 π λ q = — sin ( — ) 4 π λ 2 θ 2 q x = — [ cos cos ( α f ) cos cos (2 θ f ) - cos cos ( α i ) ] 2 π λ y — cos cos ( f ) si sin (2 θ f ) 2 λ q z = — [ sin sin ( α f ) sin sin ( α i ) ] 2 π λ