Thermoelectric Properties of Indium and Gallium Dually Doped ZnO Thin Films

• DOI: 10.1021/acsami.6b10591
• Publication Date: 2016-11-18T17:09:32Z
• Authors: Nhat Hong Tran Ng...; Truong Huu Nguyen; Yi-ren Liu; Masoud Aminzare; Anh Tuan Thanh Pham; Sunglae Cho; Deniz P. Wong; Kuei-Hsien Chen; Tosawat Seetawan; Ngoc Kim Pham; Hanh Kieu Thi Ta; Vinh Cao Tran; Thang Bach Phan
• Keywords: 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences; 3. Good health

We investigated the effect of single and multidopants on the thermoelectrical properties of host ZnO films. Incorporation of the single dopant Ga in the ZnO films improved the conductivity and mobility but lowered the Seebeck coefficient. Dual Ga- and In-doped ZnO thin films show slightly decreased electrical conductivity but improved Seebeck coefficient. The variation of thermoelectric properties is discussed in terms of film crystallinity, which is subject to the dopants' radius. Small amounts of In dopants with a large radius may introduce localized regions in the host film, affecting the thermoelectric properties. Consequently, a 1.5 times increase in power factor, three times reduction in thermal conductivity, and 5-fold enhancement in the figure of merit ZT have been achieved at 110 °C. The results also indicate that the balanced control of both electron and lattice thermal conductivities through dopant selection are necessary to attain low total thermal conductivity.