Аннотация:Topological insulators (TI) constitute a new class of materials that are characterized by the presence of stable(topologically protected) edge surface states of electrons. TI, as well as semiconductor materials can be used formanufacturing photoconductive antennas for generation and detection of terahertz radiation. Therefore, study of thedynamics of hot electrons is very important for understanding the basic mechanisms of carrier relaxation. TI filmswere grown by MOCVD method: p-type Bi2Te3, n-type Bi2Se3, and Bi1.4Sb0.6Te1.5Se1.5 (BSTS) near the Ren’scurve on the structure-composition diagram. The ultrafast dynamics of carriers in topological insulators uponexcitation by short optical pulses with photon energies above and below the band gap is studied. It is shown forBi2Te3 and Bi2Se3 that bulk states contribute to the slow relaxation dynamics, while for bulk insulator BSTSterahertz-induced dynamics is mostly driven through Dirac states on the surface with much higher relaxation rates.