On the preparation and electrical properties of thallium bismuth diselenide crystals

Thallium bismuth diselenide (TlBiSe₂) crystals were grown by an optimized process based on Bridgman technique. The material has been characterized by X-ray powder diffraction. An investigation was done on the influence of temperature on the electrical conductivity and Hall effect. The energy gap as well as the ionization energy was calculated. The electrical conductivity temperature dependence was tested to determine the dominant mechanism of conductivity in a temperature range of 203 K and 338 K. Our outcomes show an n-type semiconducting behaviour due to a degenerate state. The scattering character of the free carriers was defined by determination Hall mobilities, the concentration of carriers, activation energies of donors, the diffusion coefficient, and diffusion length of majority carriers. The performed characterization confirms that the grown TlBiSe₂ crystals are narrow gap semiconductors with promising properties for practical application.