Improved Hole Density and Electrical Properties of Bi0.64Sb1.36Te3 Epitaxial Thermoelectric Thin Films via in-situ Annealing

doi:10.15541/jim20260160

Abstract

Abstract: p-type (Bi,Sb)₂Te₃ thin films serve as an important material platform for the research of thin-film thermoelectric devices, and the optimization of their performances has attracted extensive attentions in the thermoelectric community. Thermal annealing is regarded as an effective strategy to simultaneously optimize hole concentration and crystalline quality, yet its optimization effect is usually unsatisfactory. To explore the underlying mechanism, p-type Bi_0.64Sb_1.36Te₃ thin films with high crystalline quality and optimized composition were fabricated via molecular beam epitaxy, and the effects of annealing on their microstructure and electrical transport properties were systematically investigated. It was found that in-situ annealing at 580 K optimizes hole density and mobility at the same time, which originates from the introduction of intrinsic Bi/SbTe' antisite defects and the improvement of thin-film crystalline quality. This indicated that the optimization of point defects and crystalline quality are crucial for enhancing films’ electrical properties via annealing. The Bi_0.64Sb_1.36Te₃ thin film annealed at 580 K for 2 h possessed a hole density of 4.05×10¹⁹ cm^-3 and achieved the best overall electrical properties among all samples. Multi-valence bands participate in electrical transport, leading to an outstanding room-temperature power factor of 5.14 mW·m^-1·K^-2 which represents one of the highest values for this thin-film material system.

Key words: Bi_2-_xSb_xTe₃ based thin film, molecular beam epitaxy, in-situ annealing, electrical transport property

CLC Number:

O465

LI Xianda, WU Yichen, LIU Wei, TANG Xinfeng. Improved Hole Density and Electrical Properties of Bi_0.64Sb_1.36Te₃ Epitaxial Thermoelectric Thin Films via in-situ Annealing[J]. Journal of Inorganic Materials, DOI: 10.15541/jim20260160.

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Improved Hole Density and Electrical Properties of Bi_0.64Sb_1.36Te₃ Epitaxial Thermoelectric Thin Films via in-situ Annealing

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