Thermoelectric Module of SiGe Bulk Alloys Forming p‐n Junction at the Hot Side

Abstract

Thermoelectric power generation is a potential technology for providing green energy. It is expected to be able to convert enormous amounts of waste heat to electrical energy. To realize this technology, further increases in conversion efficiency and durability are essential. In particular, durability is a critical issue, especially for harnessing high‐temperature heat sources. Thus, a thermoelectric module of SiGe is fabricated without electrodes at the hot side, which is the main cause of aging. Electronic conduction between p‐ and n‐type elements is alternatively introduced using a direct connection, forming a p‐n junction. Sufficiently low electrical contact resistances are achieved at the p‐n junction above 300 °C due to the dissipation of the depletion layer. The conversion efficiency is 2.0% with a hot‐side temperature of 700 °C. The power‐generation performance is constant during heat‐run tests conducted at 700 and 500 °C under vacuum and air, respectively, for more than 450 h. The results demonstrate that a stable power‐generation technology using a thermoelectric module at high temperatures is established successfully.

Interface and Surface Engineering Realized High Efficiency of 13% and Improved Thermal Stability in Mg3Sb1.5Bi0.5‐Based Thermoelectric Generation Devices

“…There are two possible reasons for the decrease in R in near room temperature, i.e., the ρ of TEcM exhibits a tendency to decrease and then increase (Figure S8, Supporting Information), and the ρ c is likely to decrease as the temperature rises. [ 55 ] Additionally, the measured thermal conductivity (κ) of the TE device was slightly higher than the theoretical value. This is due to the fact that the theoretical κ is the κ of TEcM, while the measured κ includes the contribution of the Cu electrodes, TEiM, and AlN substrates.…”

Thermoelectric Modules: Key Issues in Architectural Design and Contact Optimization

“…Although, this concept of device is scarce, few instances are present where the array of pn-junctions were used. [78,[150][151][152][153][154] Fabrication of directly bonded p-and n-type materials were realized using polycrystalline FeSi 2 which facilitates the operation of the devices at high temperature and in oxidizing environment. [155] These devices possess U-shaped geometry (Figure 15B) and FeSi 2 at elevated temperature makes a metallic bonding between the n-and p-type materials.…”

“…Although, this concept of device is scarce, few instances are present where the array of pn‐junctions were used [78,150–154] . Fabrication of directly bonded p‐ and n‐type materials were realized using polycrystalline FeSi 2 which facilitates the operation of the devices at high temperature and in oxidizing environment [155] .…”

Recent Advances in the Nanomaterials, Design, Fabrication Approaches of Thermoelectric Nanogenerators for Various Applications

“…Silicongermanium alloys are the most common, with multiple studies studying the addition of germanium to silicon nanowires, [131] silicon thin films [40] and bulk silicon. [132] The primary reason for reduced thermal conductivity is due to increased alloy scattering that suppresses high-frequency phonons. [133] For example, Song et al [134] found a 40% decrease in lattice thermal conductivity in a SiGe alloy.…”