Method for controllably preparing amorphous flexible Bi-Te-Se film by adopting vacuum evaporation coating

The invention relates to a method for controllably preparing an amorphous flexible Bi-Te-Se film by adopting vacuum evaporation coating. The method comprises the following steps of (1) pressing Bi2Te2.7Se0. 3 powder with the mass percent purity of 99.99 percent into a block body under the pressure of 3 to 5 MPa; (2) ultrasonically cleaning a flexible substrate in absolute ethyl alcohol and deionized water for 5 to 10 min respectively, then taking out the flexible substrate, and blow-drying the flexible substrate with nitrogen; (3) putting the block body obtained by pressing the 0.1 to 0.2 g of Bi2Te2.7Se0. 3 material into a vacuum chamber tungsten boat of a vacuum coating machine, and adjusting the distance d between the substrate and the tungsten boat to be 8 to 11cm; (4) filling nitrogen into the vacuum chamber for 2 to 8 min, stopping filling, and then vacuumizing; (5) setting the deposition rate to be 40 to 75 nm/min and the deposition time to be 40 to 60 min on a PID controller; (6) switching on an alter