High Crystalline Quality Ta-Doped h-ZnTiO₃ Epitaxial Films: Characteristics and Application in UV Detectors

Abstract

Ta-doped h-ZnTiO 3 (h-ZnTiO 3 :Ta) films with an atomic ratio of 0−5% are grown on sapphire substrates by pulsed laser deposition. The prepared films exhibit n-type semiconductor behavior with high epitaxial crystalline quality. These films have high transparency, and their optical band gaps exceed 3.72 eV. The Hall mobility and carrier concentration of the 1% Ta-doped film are 4.6 cm 2 /(V•s) and 4.20 × 10 14 /cm 3 , respectively. The h-ZnTiO 3 :Ta filmbased metal−semiconductor−metal (MSM) photodetectors are fabricated, and their characteristics are analyzed in detail. Among them, 1% Ta-doped h-ZnTiO 3 film-based devices show the best detection performance, including responsivity of 4.23 mA/W and detectivity of 1.43 × 10 11 Jones, under the wavelength of 308 nm ultraviolet light with an optical density of 140 μW/cm 2 . The detector also has an extremely fast response time (rise time: 0.16 s and fall time: 0.04 s). This work proves that h-ZnTiO 3 :Ta epitaxial films have great application prospects in future optoelectronic devices.