Enhancing the thermoelectric performance of ZnO film by sputter-deposition of Ag nanoparticles

Abstract

Owing to the surface plasmon resonance (SPR), noble metal nanoparticles (NPs) have been intensively employed to improve the optical properties of semiconductors. In this work, Ag NPs are deposited on fully c-axis oriented ZnO film with high-crystallinity prepared by radiofrequency magnetron sputtering on glass substrates. After Ag sputtering of 15 s, the ultraviolet light emission intensity of ZnO film significantly is increased by 50% due to the SPR of Ag NPs. Moreover, the conductive behavior changes from n-type semiconductor to metal-like with room-temperature conductivity sharply increasing by nearly three orders of magnitude from 4.8 for pure ZnO film to 3400 S cm −1 for Ag-deposited ZnO film. The change of conductive behavior and the remarkable increase of the conductivity can be ascribed to isolated Ag NPs with high-density electrons which are distributed on the ZnO film, leading to an increase of carrier concentration that exceeds Mott's critical density (>10 19 cm −3 ). Hall measurements show that after Ag sputtering of 15 s, the mobility increases from about 8 to 40 cm 2 V −1 s −1 and that the carrier concentration increases from 4×10 18 to 5×10 20 cm −3 . Owing to the remarkable improvement of the conductivity, the power-factor value at room temperature is enhanced from 11.5 to 49.2 μWm −1 K −2 .

Review on grain size effects on thermal conductivity in ZnO thermoelectric materials

“…25 An average particle size of 6 nm of a thermoelectric ZnO thin-lm sputter deposition with Ag nanoparticles opened up an effective way to improve the thermoelectric performance, especially in semiconducting layers. 104 In addition, the ZnO nanoparticle size TE properties performance of cement paste was found. Aer adding the nanoparticles to the mixture, the thermal conductivity was reduced to 9% due to the lower density and crystallinity of the materials, and the electrical conductivity was increased to 37% compared to simple cement paste due to the increased ion movement.…”

Large Electrical Conductivity and Thermoelectric Power Factor of Pulsed Laser-Deposited Zn1–xGaxO Thin Films

“…They showed a TE power factor of 107.7 μW/mK 2 , despite the large electron density of 5.2 × 10 20 cm −3 . 34 A trade-off between electrical conductivity and the Seebeck coefficient of the TE thin films is very critical for realizing a large thermoelectric power factor. Herein, we investigated the thermoelectric performance of Zn electrical conductivity and the thermoelectric power factor of the Zn 1−x Ga x O thin films.…”

“…Sun et al studied the thermoelectric performance of Ag nanoparticles deposited on ZnO thin films prepared by radiofrequency magnetron sputtering on a glass substrate. They showed a TE power factor of 107.7 μW/mK 2 , despite the large electron density of 5.2 × 10 20 cm –3 …”