## 1 Introduction  
Metal chalcogenide-based materials are commonly good thermoelectric (TE) materials with a high thermoelectric figure of merit. Bismuth telluride (Bi\({}_{2}\)Te\({}_{3}\)) and its alloys ((BiSb)\({}_{2}\)(SeTe)\({}_{3}\)) are currently the most promising TE materials in bulk form, at ambient temperature region, due to their high figure of merit in comparison to other material [1]. The dimensionless figure of merit is defined as ZT = (\(S^{2}\sigma T\))/\(\kappa\), where \(S\) is the Seebeck coefficient, \(\sigma\) is the electronic conductivity, \(T\) is the temperature, and \(\kappa\) is the total thermal conductivity. Theoretical analysis and experimental explorations suggest that low dimensional materials such as nanostructures, quantum wells, quantum wires, and quantum dots should have much higher thermoelectric performance than their bulk counterparts [2; 3; 4]. The highest ZT value, for Bi\({}_{2}\)Te\({}_{3}\) based materials, thus far (\(\sim\)2.4) has been obtained in Bi\({}_{2}\)Te\({}_{3}\)/Sb\({}_{2}\)Te\({}_{3}\) superlattices [5]; however, the outstanding ZT values were not reproduced, nor is the material scalable for implementing in large-scale applications. Based on the theoretical predictions, one-dimensional nanostructures including nanowires and nanotubes could reach high ZT values (\(>\)5) [6], which has not been realized yet. A review on the synthesis of Bi\({}_{2}\)Te\({}_{3}\) nanostructures has been recently reported elsewhere [7]. Bi\({}_{2}\)Te\({}_{3}\) is normally synthesized by fusion of bismuth (Bi) and tellurium (Te) metals forming an ingot, or by powder metallurgy [8]. Arc melting, a high energy process, has been shown to be a fast and reproducible synthetic method for high performance Bi\({}_{2-x}\)Sb\({}_{x}\)Te\({}_{3}\) structures [9; 10], even combined with solidification under magnetic field, yielding textured materials [11]. Bi\({}_{2}\)Te\({}_{3}\) nanostructures with various morphologies such as nanoparticles [12; 13; 14], nanosheets [15; 16], films [17], nanowires [18], hollow nanospheres [14], nanorods [19; 20], and nanotubes [21; 22] have been prepared by various routes, including solvothermal [23] or hydrothermal method, polyol method [13], electrodeposition [19; 20], etc. Among these methods, solvothermal or hydrothermal reaction processes are performed in autoclaves and usually require long reaction time (in the order of many hours to days). Electrodeposition of nanowires/nanorods require custom-made templates with special pore structure, which will dictate the resultant particle morphology. Some of these techniques are either very energy intensive or time consuming, still limiting the bulk production of these materials for niche applications. Therefore, developing a more convenient and rapid way for the bulk scale synthesis of Bi\({}_{2}\)Te\({}_{3}\) nanostructures and its alloys is still needed. Solution chemical methods may be advantageous for the synthesis of these materials at large scale if energy effective and highly reproducible synthetic methods can be developed, which may be troubling especially when the produced volumes are large. Microwave (MW) heating has been demonstrated to be a feasible method for the synthesis of TE nanomaterials directly in the solution phase. It has been shown to make it possible to perform reactions that have been done in several hours to days in a fraction of the time using MW-assisted heating, which is very energy effective, causing an effective and rapid volume heating, avoiding the thermal fluctuations in conventional heating, creating particles with more or less similar particle size. This type of a process is also important in the field of TEs in order to systematically investigate the influence of initial particle size and morphology in the resultant microstructure and TE transport characteristics of the materials. There are few reports on the MW-assisted method for the synthesis Bi\({}_{2}\)Te\({}_{3}\). [PERSON] et al.