Open AccessInterface modification of Cr/Ti multilayers with C barrier layer for enhanced reflectivity in the water window regime
Author(s) -
Sarkar P.,
Biswas A.,
Abhara.,
Rai S.,
Modi M. H.,
Bhattacharyya D.
Publication year - 2021
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577520013429
Subject(s) - specular reflection , materials science , water window , x ray reflectivity , barrier layer , synchrotron radiation , wavelength , layer (electronics) , diffusion barrier , optics , reflectivity , absorption (acoustics) , optoelectronics , thin film , nanotechnology , composite material , physics
The influence of a carbon barrier layer to improve the reflectivity of Cr/Ti multilayers, intended to be used in the water window wavelength regime, is investigated. Specular grazing‐incidence X‐ray reflectivity results of Cr/Ti multilayers with 10 bilayers show that interface widths are reduced to ∼0.24 nm upon introduction of a ∼0.3 nm C barrier layer at each Cr‐on‐Ti interface. As the number of bilayers increases to 75, a multilayer with C barrier layers maintains almost the same interface widths with no cumulative increase in interface imperfections. Using such interface‐engineered Cr/C/Ti multilayers, a remarkably high soft X‐ray reflectivity of ∼31.6% is achieved at a wavelength of 2.77 nm and at a grazing angle of incidence of 16.2°, which is the highest reflectivity reported so far in the literature in this wavelength regime. Further investigation of the multilayers by diffused grazing‐incidence X‐ray reflectivity and grazing‐incidence extended X‐ray absorption fine‐structure measurements using synchrotron radiation suggests that the improvement in interface microstructure can be attributed to significant suppression of inter‐diffusion at Cr/Ti interfaces by the introduction of C barrier layers and also due to the smoothing effect of the C layer promoting two‐dimensional growth of the multilayer.