Structure and crystallization of an amorphous film of variable thickness Bi2Te3with a copper sublayer under the action of an electron beam in TEM

Abstract

Nanothin films of bismuth telluride Bi2Te3 were obtained by thermal sputtering in vacuum on a mica substrate with amorphous carbon and a copper sublayer. A sample with a specially created sharp thickness gradient was studied by transmission electron microscopy (TEM). An island-labyrinth structure of the film was revealed, with the size of islands in the range of about 7-25 nm. The film is amorphous at the beginning of the thickness gradient; in the studied regions of greater thickness, it crystallizes in the rhombohedral Bi2Te3 phase. High-resolution TEM has revealed crystallization of initially amorphous islands under the action of a focused electron beam of increased intensity in an electron microscope column. © 2021 Author(s).