Single crystals of CuBr doped n-type 85% Bi₂Te₃-15% Bi₂Se₃ with various doping concentration have been prepared and the temperature dependences of the electrical resistivity, carrier mobility and Hall coefficient have been characterized at temperatures ranging from 77K to 600K. Undoped 85% Bi₂Te₃-15% Bi₂Se₃ single crystal exhibited a transition from p-type to n-type at 430K. With doping 0.03-0.1 wt% CuBr to 85% Bi₂Te₃ -15% Bi₂Se₃, n-type conduction occurred at all temperatures. With addition of CuBr, the electron concentration of 85% Bi₂Te₃ -15% Bi₂Se₃ increased with the relationship as n_i=10.2×10^(20) CuBr(wt%). The scattering parameter and the ratio of the electron and hole mobility (e/ h) of 85% Bi₂Te₃-15% Bi₂Se₃ were determined as 0.1 and 1.45, respectively. The bandgap energy at OK was found as 0.245 eV.