【Device Papers】Enhanced charge transfer across the dual interface of Ga₂O₃@TiO₂/Ti₃C₂ heterojunction for self-powered deep-ultraviolet photodetector

      Researchers from the Chongqing Key Laboratory of Multi-Scale Manufacturing Technology have published a dissertation titled "Enhanced charge transfer across the dual interface of Ga₂O₃@TiO₂/Ti₃C₂ heterojunction for self-powered deep-ultraviolet photodetector" in Materials Today Communications.

Abstract

      Fabricating heterojunctions between Ga₂O₃ and other materials facilitates the self-powering capabilities and improves the energy efficiency of deep-ultraviolet photodetector photodetectors. Herein, a dual built-in electric field is engineered at the junction of a 3D Ga₂O₃ nanowires network with 2D TiO₂ and Ti₃C₂ nanosheets, enhancing the rapid charge transport under the self-powered mode. The optimal Ga₂O₃@TiO₂/Ti₃C₂ heterostructure photodetector with suitable contents of TiO₂ and Ti₃C₂ is constructed by spin coating 2D TiO₂/Ti₃C₂ nanosheets on Ga₂O₃ nanowire-network, resulting in a self-powered responsivity of 18.90 mA W⁻¹ and a detectivity of 1.06 × 10¹² Jones, which is attributed to the formed dual heterojunction interface. In addition, Ga₂O₃@TiO₂/Ti₃C₂ shows the highest photo-to-dark current ratio (5199.00), responsivity (649.88 mA W⁻¹), detectivity (1.48 × 10¹³ Jones), and external quantum efficiency (317.44 %) at 10 V bias, which are 3.99, 74.86, 17.30 and 74.86 times than pure MSM-type Ga₂O₃ nanowires photodetector. Ga₂O₃@TiO₂/Ti₃C₂ photodetector also exhibits superior responsivity compared with Ga₂O₃@Ti₃C₂ photodetector, suggesting that the double built-in electric field enhances charge transfer more effectively than a single built-in electric field. Ga₂O₃@TiO₂/Ti₃C₂ photodetector also exhibits good detection stability. Computational results, including charge density difference, work functions, and band structures, clarify the formation mechanism of dual built-in electric fields and highlight their crucial role in accelerating the separation and transfer of photogenerated electrons. These results highlight the effectiveness of developing dual built-in electric field heterojunction photodetectors in facilitating self-driven operation and improving photoelectric conversion efficiency.

DOI：

https://doi.org/10.1016/j.mtcomm.2024.111065