Tellurium dioxide (TeO2) is a crystalline solid material that is used as a substrate in various optical and electronic applications. It is known for its high transparency in the infrared region and its good thermal stability, making it suitable for use in high temperature applications. TeO2 substrates are commonly used in optical components, such as infrared filters and beam splitters, as well as in photovoltaic cells and thermoelectric materials. The properties of TeO2 substrates can be further improved through doping with impurities, such as zinc or tin, to enhance their electrical conductivity.