Effect of Antimony Buffer Layer on the Electric and Magnetic Properties of 200 and 600 nm Thick Bismuth Films on Mica Substrate

Materials (Basel). 2020 Apr 25;13(9):2010. doi: 10.3390/ma13092010.


We report on the production of 200 and 600 nm thick Bi films on mica substrate with 10 nm thick Sb sublayer between Bi and mica. Two types of films have been studied: block and single crystal. Films were obtained using the thermal evaporation technique using continuous and discrete spraying. Discrete spraying allows smaller film blocks size: 2-6 μ m compared to 10-30 μ m, obtained by the continuous spraying. Single crystal films were made by the zone recrystallization method. Microscopic examination of Bi films with and without Sb sublayer did not reveal an essential distinction in crystal structure. A galvanomagnetic study shows that Sb sublayer results in the change of Bi films properties. Sb sublayer results in the increase of specific resistivity of block films and has no significant impact on single crystal films. For single-crystal films with Sb sublayer with a thickness of 200 nm the Hall coefficient has value 1.5 times higher than for the 600 nm thickness films at 77 K. The change of the Hall coefficient points to change of the contribution of carriers in the conductivity. This fact indicates a change in the energy band structure of the thin Bi film. The most significant impact of the Sb sublayer is on the magnetoresistance of single-crystal films at low temperatures. The increase of magnetoresistance points to the increase of mobility of the charge carriers. In case of detecting and sensing applications the increased carriers mobility can result in a faster device response time.

Keywords: bismuth; galvanomagnetic properties; hall coefficient; relative magnetoresistance; resistance; thin film.