Hard X-ray resonant reflectivity studies of ultrathin WS_(2) layers grown by pulsed laser deposition  

作　　者：Sergey M.Suturin Polina A.Dvortsova Alexander M.Korovin Vladimir V.Fedorov Evgeniya Yu.Lobanova Nikolai S.Sokolov 

机构地区：[1]ITMO University,49 Kronverksky prospekt,197101 St.Petersburg,Russia [2]Alferov University,8/3 Khlopina,194021 St.Petersburg,Russia

出　　处：《Journal of Semiconductors》2025年第3期102-108,共7页半导体学报(英文版)

基　　金：supported by the Ministry of Science and Higher Education of the Russian Federation(agreement No.075-15-2021-1349)。

摘　　要：Synchrotron method of resonant X-ray reflectivity 2D mapping has been applied to study ultrathin epitaxial layers of WS_(2)grown by pulsed laser deposition on Al_(2)O_(3)(0001)substrates.The measurements were carried out across the L absorption edge of tungsten to perform depth-dependent element-selective analysis sensitive to potential chemical modification of the WS_(2)layer in ambient conditions.Despite the few monolayer thickness of the studied film,the experimentally measured maps of reflectance as a function of incident angle and photon energy turned out to be quite informative showing well-pronounced interference effects near W absorption edge at 10210 eV.The synchrotron studies were complemented with conventional non-resonant reflectance measurements carried out in the laboratory at a fixed photon energy corresponding to Cu Kαemission.The reconstruction of the depth and energy dependent scattering length density within the studied multilayers was carried out using the OpenCL empowered fitting software utilizing spectral shaping algorithm which does not rely on the pre-measured reference absorption spectra.A thin WO_(x) layer has been revealed at the surface of the WS_(2)layer pointing out to the effect of water assisted photo-oxidation reported in a number of works related to ultrathin layers of transition metal dichalcogenides.

关 键 词：transition metal dichalcogenides epitaxial multilayers pulsed layer deposition resonant X-ray reflectivity non-destructive depth profiling 

分 类 号：TN2[电子电信—物理电子学]