Electron-beam irradiation–induced quasi-annealing enables enhanced thermoelectrics in commercial <i>n</i> -type Bi2Te2.7Se0.3

Abstract

Commercial n-type Bi2Te2.7Se0.3 is widely employed for near-room-temperature thermoelectric (TE) applications; however, its TE performance remains inferior to that of p-type Bi0.5Sb1.5Te3, resulting in a pronounced p–n mismatch in Bi2Te3-based TE devices. Here, we report a simple, scalable, and composition-invariant post-treatment via high-energy electron-beam irradiation to enhance the TE performance of n-Bi2Te2.7Se0.3. The improvement originates from an irradiation-induced quasi-annealing effect associated with high-energy electron–electron-cloud interactions, whereby an appropriate dose enhances structural ordering, suppresses carrier scattering, and markedly enhances carrier mobility, thereby optimizing electrical transport. At an optimal dose of 400 kGy, the sample achieves a peak ZT of ∼1.35 at 353 K, a room-temperature ZT of ∼1.24, and an average ZTavg of ∼1.29 over 303–403 K. This work establishes electron-beam irradiation as an efficient and environmentally benign strategy for optimizing commercial n-type Bi2Te2.7Se0.3, offering practical implications for high-efficiency TE device applications.