Abstract：We present an optical spectroscopy study on Bi2Se3, Bi2Te3, Sn-doped Bi2Te3 and Cu-intercalated Bi2Se3 crystals grown by self-melting. We find that the plasma edge of Bi2Se3 slightly shifts to lower energy with decreasing temperature. The Cu-intercalated Bi2Se3 shows a superconducting transition near 3.1 K. Optical spectroscopy measurement shows that the plasma edge shifts substantially to higher frequency 1250 cm?1 indicating that Cu-doping supplies extra electrons to the system and further shifts the chemical potential up. Furthermore, our measurement reveals that the plasma edge of Bi2Te3, Sn doped Bi2Te3?δSnδ(δ=0.67%) and Cu-intercalated Bi2Se3 shift slightly to higher energies with decreasing temperature. Combined with the band calculation, we attribute the blue-shift primarily to the reduction of effective mass of carriers with decreasing temperature. The optical data yield useful information about the bulk electronic band structure of the superconducting doped topological insulator CuxBi2Se3 (x=0.14).
2013, Vol. 30 
