  We have studied the carrier transport in two topological insulator (TI)
Bi$_{2}$Te$_{3}$ microflakes between 0.3 and 10 K and under applied backgate
voltages ($V_{\rm BG}$). Logarithmic temperature dependent resistance
corrections due to the two-dimensional electron-electron interaction effect in
the presence of weak disorder were observed. The extracted Coulomb screening
parameter is negative, which is in accord with the situation of strong
spin-orbit scattering as is inherited in the TI materials. In particular,
positive magnetoresistances (MRs) in the two-dimensional weak-antilocalization
(WAL) effect were measured in low magnetic fields, which can be satisfactorily
described by a multichannel-conduction model. Both at low temperatures of $T <
1$ K and under high positive $V_{\rm BG}$, signatures of the presence of two
coherent conduction channels were observed, as indicated by an increase by a
factor of $\approx$ 2 in the prefactor which characterizes the WAL MR
magnitude. Our results are discussed in terms of the (likely) existence of the
Dirac fermion surface states, in addition to the bulk states, in the
three-dimensional TI Bi$_2$Te$_3$ material.
