p–n Junctions have been widely used in the construction of high-performance TiO₂ ultraviolet photoelectric detector devices, especially NiO/TiO₂ heterostructures. In this work, two devices with different structures were constructed to investigate the effects of the growth of NiO above (S-TN) and below (D-NT) the TiO₂ array on the device performance, and the D-NT device showed better performance. The D-NT device exhibited a lower dark current, with a decrease of approximately an order of magnitude compared with S-TN PD and TiO₂ nanoarray (NA) PDs. The D-NT heterojunction device demonstrated a large on–off ratio of 5.4 × 10⁴, a high detection sensitivity of 1.44 × 10¹⁴ Jones, and a fast photoresponse time of 2 s under UV light illumination. Interestingly, the D-NT device also displayed self-powered performance, and its photoresponse time was 0.1 s. The dense and uniform NiO film deposited on the FTO substrate not only forms a built-in potential field with the TiO₂ NAs, but it also provides greater uniformity and stability to this built-in potential field compared to a NiO layer spin-coated on TiO₂ NAs, which may be the main reason for the high performance of the D-NT photodetector. The device in which NiO was grown below the TiO₂ array provides a fundamental basis for the future development of all-solid-state photodetectors.

中文翻译：

---

高性能 NiO/TiO2 紫外光电探测器：NiO 层位置的影响

p-n结已广泛用于构建高性能TiO ₂紫外光电探测器器件，尤其是NiO/TiO ₂异质结构。在这项工作中，构建了两个不同结构的器件来研究 NiO 在 TiO ₂阵列上方 (S-TN) 和下方 (D-NT) 的生长对器件性能的影响，D-NT 器件表现出更好的性能表现。D-NT 器件表现出较低的暗电流，与 S-TN PD 和 TiO ₂纳米阵列 (NA) PD相比降低了大约一个数量级。D-NT异质结器件具有5.4×10 ⁴的大开关比和1.44×10 ¹⁴的高检测灵敏度Jones，以及在紫外光照射下 2 秒的快速光响应时间。有趣的是，D-NT 装置也表现出自供电性能，其光响应时间为 0.1 s。沉积在 FTO 基板上的致密均匀的 NiO 膜不仅与 TiO ₂ NA形成了内置势场，而且与旋涂在其上的 NiO 层相比，它还为该内置势场提供了更大的均匀性和稳定性。 TiO ₂ NAs，这可能是 D-NT 光电探测器高性能的主要原因。NiO 在 TiO ₂阵列下方生长的器件为全固态光电探测器的未来发展提供了基础。