N-type Bi₂Te₃₋ₓSeₓ (x = 0.3, 0.6, 0.7) thermoelectric materials and ball-milled N-type Bi₂Te₂.₃Se₀.₇ were prepared to investigate their thermoelectric properties. The effects of different processing methods on the crystal structure, thermoelectric properties, and microstructural morphology of N-type Bi₂Te₃ thermoelectric materials were investigated. X-ray diffraction analyses confirmed that all samples exhibited diffraction patterns consistent with the standard crystal structure. Electrical conductivity decreased with increasing temperature for all samples. Among them, the ball-milled sample exhibited the highest electrical conductivity of 233 × 10³ S·m⁻¹. Thermal conductivity reached its minimum at 310 K for all samples and increased thereafter with temperature. The ball-milled sample had the lowest thermal conductivity of 1.34 W/m·K. The figure of merit (ZT) increased with temperature for all samples. The ball-milled sample achieved the highest ZT of 0.132 at 400 K. It can be suitable for thermoelectric sensor applications.