▎ 摘　　要

Crystalline quasi-2D Ti-delta-doped gamma-alumina (2D-Ti:gamma-alumina) is synthesized by a facile, precursor-alternating atomic-layer-deposition technique followed by a post-growth air-anneal at approximate to 800 degrees C. According to energy-dispersive X-ray spectroscopy maps, Ti atomic concentration remains uniform and approaches approximate to 1.5%. Subject to several UV-light exposures, the samples are found to develop a full strength, stable emission in the ultrawide spectral range of approximate to 350-850 nm. The near-infrared (NIR) emission band centered at approximate to 760 nm is assigned to Ti deep defect states introduced in the alumina host. According to photoluminescence excitation-emission studies, aggregate oxygen vacancies remain a primary excitation source of the NIR emission. In addition, a broad visible-range emission band at approximate to 525 nm is registered in the temperature range of approximate to 108-348 K, but unlike the NIR band, its temperature dependence remains Arrhenius with the non-radiative recombination activation energy of approximate to 73 +/- 9 meV. The resultant 2D-Ti:gamma-alumina holds promise for applications in low-cost alumina-based optoelectronics, photocatalytic remediation, and spectrally wide light sources.