oxidesemiconductor

Oxide semiconductors are semiconducting materials composed primarily of metal oxides. They often feature wide band gaps and predominantly n-type conduction, a result of intrinsic defects such as oxygen vacancies or donor dopants. Oxide semiconductors can be crystalline or amorphous and are used in a range of electronic and optoelectronic applications. Common examples include zinc oxide (ZnO), tin oxide (SnO2), indium oxide (In2O3), and gallium oxide (Ga2O3), as well as multi-component systems such as indium gallium zinc oxide (IGZO), which is widely used in thin-film transistor applications.

Materials in this class vary in structure and properties. ZnO typically adopts a wurtzite structure with a direct band gap, while SnO2 has a rutile structure, In2O3 a bixbyite-type oxide, and Ga2O3 exists in several polymorphs with an even wider band gap. IGZO combines multiple oxides and is commonly processed as an amorphous semiconductor, enabling high electron mobility in thin-film transistors. The optical transparency of many oxide semiconductors in the visible range makes them appealing for transparent electronics and related technologies.

Electronic behavior in oxide semiconductors is strongly influenced by defect chemistry and stoichiometry. While n-type conduction is common, achieving stable p-type oxide semiconductors remains challenging due to intrinsic defects. Processing methods such as sputtering, pulsed laser deposition, chemical vapor deposition, and sol-gel enable deposition on diverse substrates, including glass and flexible plastics.

Applications include thin-film transistors for displays, transparent electronics, UV photodetectors, gas sensors, and as components in photovoltaics or photocatalysis. Ongoing research aims to improve mobility, stability, and defect control, and to expand the range of oxide semiconductors suitable for complementary electronic systems.