Thermoelectric behaviors of ZnO mesoporous thin films affected by strain induced from the different dopants radii (Al, Ga, and In)

ABSTRACT

This study considered effects from thermoelectric property changes due to mesoporous thin film ZnO lattice deformation through dopingwith various group III elements. The distorted hexagonal wurtzite structure occurred in the ZnO thin film due to ion size differencesbetween Zn and other doping elements. These strains cause distortion, resulting in reduced mobility because they inhibit grain growth andreduce crystallinity. Al doping induced the largest strain since it represented the largest ionic radius difference from Zn, whereas straindifferences between Ga and In doped ZnO were almost negligible. In is larger than Zn, whereas Al and Ga dopants have a smaller atomicradius. Thus, carrier concentration for the smaller ion was 18%–26% higher than for the larger ion, and electroconductivity and carrierconcentration increased 2–3.5- and 5–10-fold, respectively, with increasing dopant concentration, regardless of the doping element. Ga wasthe best candidate among the group III elements for doping a ZnO thin film, achieving the highest power factor of 8.01 at 323 K. We verifiedthat thermoelectric properties could be improved by controlling dopant concentration, being influenced from inducing crystal lattice deformation through ion radius differences between the dopant and Zn.

논문정보

Cite as: Appl. Phys. Lett. 119, 193902 (2021)

Submitted: 15 July 2021 . Accepted: 21 October 2021 .Published Online: 8 November 2021

Authors:  Min-Hee Hong, Haryeong Choi, Younghun Kim, Dong Il Shim, Hyung Hee Cho, and Hyung-Ho Park

DOI : https://doi.org/10.1063/5.0063497