TeO2: A Prospective High‐k Dielectric

Herein, high‐ k dielectric behavior of TeO 2 thin films is investigated. The films are prepared using pulsed laser deposition on indium tin oxide (ITO)–glass substrates. Increasing the growth temperature has improved the surface roughness, transparency, and bandgap of the films. Films grown at 500 °C display nanocrystalline nature which is reflected in the increase of bandgap to 4.7 eV and is higher than the bulk value of α‐TeO 2 (3.7 eV). The nanocrystalline TeO 2 films in the metal–insulator–metal configuration show a stable high permittivity of ≈19 with low leakage current ( J < 1 × 10 −7 A cm −2 ) and good voltage stability ( α = 509 ppm V −2 ). Field‐effect modulation is observed in the metal–oxide–semiconductor stack configuration with tellurium as a semiconductor. The study suggests nanocrystalline TeO 2 as a low‐temperature processable high‐ k material with high transparency for transistor applications.