Nano tree-like branched structure with α-Ga2O3 covered by γ-Al2O3 for highly efficient detection of solar-blind ultraviolet light using self-powered photoelectrochemical method

• Published in: Applied surface science 2021-03, Vol.541, p.148380, Article 148380
• Main Authors: Zhang, Junhua, Jiao, Shujie, Wang, Dongbo, Gao, Shiyong, Wang, Jinzhong, Zhao, Liancheng
• Format: Article
• Language: English
• Subjects: Photoelectrochemical; Solar-blind ultraviolet detection; Surface modification; Wide-bandgap semiconductor materials
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.148380

[Display omitted] •Nano tree-like branched structure with α-Ga2O3-γ-Al2O3 was synthesized through simple hydrothermal method.•γ-Al2O3 modifying the surface of α-Ga2O3 for blocking electrons to electrolyte and reducing the recombination.•The performance of self-powered detector based on α-Ga2O3/γ-Al2O3 improved over 100%, compared with α-Ga2O3. For photoelectrochemical ultraviolet detector, carrier recombination, low light trapping efficiency and long-distance charge carries transport are the main factors restricting its detection performance. Herein, a novel tree-like branched structure with α-Ga2O3 covered by γ-Al2O3 has been successfully fabricated by simple two-step hydrothermal treatment and applied into the self-powered photoelectrochemical solar-blind detector. Owning to the introduction of γ-Al2O3 layer with ultra-wide bandgap to coat outside of α-Ga2O3, an energy barrier has been established at the semiconductor/electrolyte interface accelerating the photogenerated carriers separation and thus suppressing interfacial charge recombination. Besides, the obtained tree-like branched structure significantly expands the contact surface area between carries and electrolyte to shorten the distance of charge transport improving response speed and brings a larger specific surface area to capture and scatter incident photons enhancing light absorption. Campared with the pure α-Ga2O3, the α-Ga2O3-γ-Al2O3 based on the photoelectrochemical device shows higher responsivity, larger photocurrent density and faster response time to solar-blind ultraviolet signal, some performance improvements exceed 100%, indicating the highly efficient detection.