XXIX Symposium "Nanophysics and Nanoelectronics" in Nizhny Novgorod, March 10-14, 2025
Experimental instruments and technique

Changes in the atomic composition of materials under high-energy electron irradiation in an electron microscope

K. E. Prikhod'ko^ab, M. M. Dementyeva<sup>a

a</sup> National Research Centre "Kurchatov Institute", Moscow
^b National Engineering Physics Institute "MEPhI", Moscow

Abstract: The effect of high-energy electron irradiation (200 keV) in situ in a TEM (transmission electron microscope) column on samples of bismuth oxide BiO$_2$ polycrystalline films and copper oxide CuO films, as well as on thin samples of tantalum disulfide TaS$_2$ has been studied. It was found that the impact of beam electrons causes preferential displacements of light atoms from the crystal lattice nodes (for which the transferred energy $E_t$ exceeds the threshold displacement energy $E_d$) in the direction of the electrons initial movement, which causes their successive removal from the sample volume and initiates the formation of phases with a reduced content of light atoms. BiO$_2$ samples undergo phase transformation into bismuth oxide Bi$_2$O$_3$, the first signs of which appear at fluence of 1.5 $\cdot$ 10$^{23}$ e/cm$^2$, and with increasing irradiation fluence up to 3.5 $\cdot$ 10$^{23}$ e/cm$^2$ this transformation spreads deep into the sample. At irradiation of CuO samples up to fluence 0.55 $\cdot$ 10$^{23}$ e/cm$^2$ copper oxide of Cu$_2$O composition is formed, and at fluence 3.3 $\cdot$ 10$^{23}$ e/cm$^2$ – metallic copper. Phase transformations in TaS$_2$ occur at an irradiation fluence of 1.74 $\cdot$ 10$^{23}$ e/cm$^2$ with the formation of TaS. A model of the process of light atoms removal from the sample under the action of electron irradiation has been developed. Within the framework of the developed model, the threshold displacement energy $(E_d)$ values of oxygen atoms was found to be 31.3 eV in BiO$_2$, 21.5 eV in CuO, and for sulfur atoms 15.2 eV in TaS$_2$.

Received: 30.04.2025
Revised: 30.04.2025
Accepted: 30.04.2025

DOI: 10.61011/JTF.2025.10.61347.89-25

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