@article{Nozawa2026, 
author = {Koki Nozawa and Masayuki Murata and Takashi Suemasu and Kaoru Toko},
title = {Record-high power factors in low-temperature polycrystalline Ge for flexible thermoelectric generators},
year = {2026},
journal = {Journal of Materiomics},
volume = {12},
number = {3},
keywords = {Electrical properties, Flexible devices, Polycrystalline Ge thin films, Solid-phase crystallization, Thermoelectric generators},
url = {https://www.sciopen.com/article/10.1016/j.jmat.2026.101211},
doi = {10.1016/j.jmat.2026.101211},
abstract = {Flexible thermoelectric devices offer unique advantages, including mechanical conformability and suitability for wearable and Internet of Things energy harvesting. However, their integration with low-cost polymer substrates requires the low-temperature synthesis of high-performance thermoelectric materials. In this study, impurity-doped polycrystalline Ge thin films were fabricated via solid-phase crystallization at low temperatures (<500 ℃), and their microstructure and transport properties were systematically optimized by controlling the dopant concentration and deposition temperature. As a result, both P-doped n-type and Ga-doped p-type Ge films achieved record-high power factors of 3180 μW·m−1·K−2 and 1210 μW·m−1·K−2, respectively, establishing the highest performance reported to date among polycrystalline, environmentally benign thermoelectric materials. The flexible devices demonstrated stable power generation, achieving maximum power densities of 0.70 mW·cm−2 in the cross-plane configuration, which represent the highest output characteristics among eco-friendly flexible thermoelectric systems. These results establish low-temperature solid-phase crystallization of doped Ge thin films as a promising route to next-generation flexible thermoelectric devices.}
}