Effects of Thallium-Aluminum-Codoped Zinc Oxide Thin Film as a New Transparent Conducting Oxide

摘要

Herein, the electro-optical properties of sol-gel spin-coated “thallium- aluminum-codoped zinc oxide (TAZO)” focusing on the effects of thallium are investigated. It is shown that the amount of thallium (TI) has a significant effect on improving the electrical properties of TAZO as a new transparent conducting oxide (TCO). The optimum results are achieved by adding 1 at% of TI to aluminum- doped zinc oxide (AZO), after which the sheet resistance (Rs) value is reduced from 30.21 to 2.832 KΩ sq~(-1). Although less Rs is recorded in all amounts of TI used (from 1 to 4 at%) than in TI-free samples, Rs also increases as the amount of TI increases, which is related to the degradation of the crystal structure at higher values of TI. In view of a trade-off between electrical conductivity and optical transparency, a decrease in transparency in the presence of TI is a predictable issue, but while the Tl-free samples record 90% transparency, the uniform thin film of 1 at% TI-AZO is able to achieve 85% transparency. This small amount of reduction in transparency shows the high potential of TI to improve the properties of AZO as a TCO.