Bi-rich Bi 2 Te 3 thin films are prepared at 300 K using e-beam evaporation technique. A source power of 45 W for e-beam is used. Post deposition, these as-deposited Bi-rich Bi 2 Te 3 (Bi-BT-AD) films are annealed at 100 °C (Bi-BT-100), 200 °C (Bi-BT-200) and 300 °C (Bi-BT-300) for 1 h under a pressure of 3 × 10 −4 Pa. X-ray diffraction measurements reveal the presence of Bi phase together with crystalline Bi 2 Te 3 indicating the possible presence of Bi-rich Bi 2 Te 3 phase in the Bi-BT-AD film. The broad peaks from Bi 2 Te 3 (015) plane indicate nanocrystalline nature of particles. With annealing, no change in diffraction pattern is observed for Bi-BT-100. However, Bi-BT-200 and Bi-BT-300 films show the emergence of x-ray reflection from unknown phases around 2θ ~ 20° and 47°. This indicates Bi related secondary phase segregation and the thermodynamic instability for the presence of Bi in Bi 2 Te 3 lattice. From Raman studies it is discerned that Bi secondary phase coexists along with the Bi-rich Bi 2 Te 3 nanocrystalline grains. On vacuum annealing Bi-rich Bi 2 Te 3 phase in thin films prevails as evidenced from the p-type electrical characteristics, while excess Bi disappears and converts into an unknown minor phase. The resistivity of all the annealed films are ~ 0.9 × 10 −4 Ωcm. The Seebeck coefficients also do not show any change and remain around 33 to 36 μV/K. Thermoelectric properties of Bi-BT-100 exhibit high power factors when measured at different ΔT with a maximum of ~ 17.5 × 10 −4 W/K 2 m for ΔT = 100 °C. Thus, unlike the near-stoichiometric thin films, Bi-rich thin films require low temperature annealing (~100 °C) to achieve optimized parameters. Bi-rich Bi 2 Te 3 thin films also show higher power factor compared to the near-stoichiometric thin films. Thus, favourable thermoelectric properties can be achieved at 300 K for temperature sensitive device fabrication using Bi-rich Bi 2 Te 3 thin films.