XRR/XRF ( X-ray reflectometry /X-ray fluorescence) with Correct Solutions 2024

XRR/XRF ( X-ray reflectometry /X-ray fluorescence) with Correct Solutions 2024 X ray reflectometry is no a technique to evaluate what? - Answer -Diffraction phenomena What is XRR used for? - Answer -Used to analyze angle dependent X-ray reflectivity from grazing incident x-ray beam to determine thin-film parameters including thickness, density, and surface roughness XRR is similar to XRD theta- 2 theta except - Answer -Small incident angle theta 0-5 degrees What can XRR characterize? - Answer -1) Study single crystalline, polycrystalline or amorphous material 2) Evaluate surface roughness and interface width nondestructivity 3) Can be used to study opaque film 4) Used to determine the layer structure of multilayer single film 5) Can be used to measure film thickness from several 1000nm with high precision XRR is better at looking at what compared to ellipsometry? - Answer -Better at looking at opaque films - similar info from elipsometry but can see deeper in material XRR compared to SEM - Answer -XRR has high precision 1000 nm vs SEM 10 nm limit For x-rays n=1 - sigma 1 and sigma is on an order of what? - Answer -10 ^-5 Dispersion vs absorption orders? - Answer -Dispersion 10 ^-5 Absorption is 10^-6 Dispersion is proportional to what? - Answer -Dispersion is proportional to density What leads to interference fringes in reflectivity spectrum in thin films? - Answer -For a film on substrate interference between reflections off the top and bottom surfaces of the film lead to this How does interference fringes respond to thicker films? - Answer -Greater film thicknesses result in more closely packed interference fringes Surface roughness reduces what in XRR? - Answer -Surface roughness reduces the magnitude of interference induces reflectivity oscillation What is photoluminescence? - Answer -Luminescence after sample is excited by ligh