Britannica Sources used in this answer

How do chalcogenide glasses support xerography and electronic switching devices?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

How to properly care for contact lenses — amorphous solid Learn about the chemistry of contact lenses and why it is important to keep them clean.

Chalcogenide glasses are a class of noncrystalline, nonoxide materials formed by melting chalcogen elements—such as sulfur, selenium, or tellurium—with elements from groups IV or V of the periodic table. They function as amorphous semiconductors, a property that enables their use in specific electronic and imaging technologies.12

Xerography

Chalcogenide glasses, particularly amorphous selenium and arsenic selenide, serve as the photoconducting element in xerography. These materials act as electrical insulators in the dark but become conductive when exposed to light. In the xerographic process, this photoconductive layer is used to create an electrostatic image of a document, which is then developed into a physical copy. This technology remains fundamental to the operation of plain-paper copiers and laser printers.3

Electronic Switching

Due to their semiconducting nature, chalcogenides are utilized in threshold and memory switching devices. Their electronic conductivity is primarily attributed to defective bonds within the glass structure, where atoms do not strictly follow their expected covalent coordination. This unique structural characteristic allows these materials to transition between different conductive states, facilitating their application in specialized electronic switching components.14