Sn-incorporation effect on thermoelectric properties of Sb-doped Ge-rich Ge_1−x−y Si _x Sn _y epitaxial layers grown on GaAs(001)

Abstract

We investigate Sn incorporation effects on the thermoelectrical characteristics of n-type Ge-rich Ge1−x−y Si x Sn y layers (x ≈ 0.05−0.1, y ≈ 0.03) pseudomorphically grown on semi-insulating GaAs(001) substrates by molecular beam epitaxy. Despite the low Sn content of 3%, the Sn atoms play a role in suppressing the thermal conductivity from 13.5 to 9.0 Wm−1K−1 without degradation of the electrical conductivity and the Seebeck coefficient. Furthermore, a relatively high power factor (maximum: 14 μWcm−1K−2 at room temperature) was also achieved for the Ge1−x−y Si x Sn y layers, almost the same as the Si1−x Ge x ones (maximum: 12 μWcm−1K−2 at room temperature) grown with the same conditions. This result opens up the possibility of developing Sn-incorporated group-IV thermoelectric devices.

Layer Exchange Synthesis of SiGe for Flexible Thermoelectric Generators: A Comprehensive Review

“…[126,137] Polycrystalline SiGeSn layers demonstrate ZT values higher than SiGe or GeSn binary alloys. [36,[138][139][140][141][142] The large Seebeck effect caused by the addition of metal nanoparticles to SiGe has been reported for a long time, [143,144] but it has recently resurfaced. [145,146] Although achieving a large Seebeck effect still requires high process temperatures, it can be lowered through the combined use of LE.…”