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The article compares carrier mobility in monocrystals, as well as monocrystal and block films of different width thus defining carrier contribution to interaction with phonons, surface, boundaries and structural defects of crystallites in bismuth films doped with tellurium. It is determined that there is a linear dependence of inverse electron mobility on inverse width of bismuth film doped with tellurium.

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The possibility of determining in-depth distribution of tellurium donor impurity in lamellar bismuth samples using the time-of-flight mass spectrometry and electron microscopy methods in the concentration range of 0.005-0.150 at. % Te is studied in the present paper. To measure the amount of tellurium in lamellar bismuth samples, we used a LUMAS-30 time-of-flight mass spectrometer with a pulsed low-pressure glow gas discharge in a combined hollow cathode and a Zeiss Evo-40 scanning electron microscope. The samples for measurements were cut from the middle of the ingots of the BiTe alloy with the required impurity concentration. The samples presented a thin plate of a size of 10 × 10 mm 2 and 1 mm thickness. The samples were thoroughly washed in distilled water and then etched in a 65 % solution of nitric acid to remove the surface layer with traces of external contaminants. The samples were strengthened as the bottom of the hollow cathode in the gas-discharge cell, where the impulse ionization of the sample atoms in a glow discharge plasma occurred. The relative error in the in-depth distribution of impurities did not exceed 6 %, while the error in determining the concentration of impurities by a mass spectrometer, according to the passport data, did not exceed 5 %. The sensitivity limit in determining the concentration of impurities in the device LUMAS-30, according to the passport data, was 10-6 at. %. As a result of research, we set that the time-of-flight mass spectrometry method gives a very accurate determination of the tellurium impurity concentration, and also allows to establish a uniform distribution of tellurium over the volume of a doped bismuth lamellar sample. The electron microscopy method using a Zeiss Evo-40 microscope does not give a uniform distribution of tellurium over the sample volume.