In this study, we report negative photoconductivity in SnO/SnSe nanosheets. We synthesized 2D n-type SnSe nanosheets by the hydrothermal route and observed highly stable and repeatable negative photoconductivity (NPC) in the presence of both visible (532 nm) and near-infrared (NIR, 905 nm) irradiation. The existence of native SnO skin on SnSe nanosheets was confirmed with X-ray photoelectron spectroscopy (XPS). Negative photoresponse was improved significantly after Au nanoparticles (∼3.4 nm) functionalization of SnO/SnSe nanosheet. Au-SnO/SnSe exhibited responsivity/detectivity of 47.55 mA/W & 1.49 × 10 Jones and 47.8 mA/W &1.5 × 10 Jones at 10 V bias in visible and NIR light intensity of 50 µW/cm, respectively, and quite a faster fall time of 841 µs and 791 µs in NIR exposure. The origin of NPC in SnSe is attributed to the trapping of photogenerated hot carriers by surface adsorption of oxygen in ambient air. The NPC was further increased due to a significant increment of dark current (as well as I/I) after Au nanoparticles functionalization on SnO/SnSe.

中文翻译：

---

可见光和近红外光下金纳米颗粒功能化 SnO2/SnSe2 纳米片的表面捕获诱导负光电导

在这项研究中，我们报告了 SnO/SnSe 纳米片的负光电导性。我们通过水热途径合成了 2D n 型 SnSe 纳米片，并在可见光（532 nm）和近红外（NIR，905 nm）照射下观察到高度稳定和可重复的负光电导（NPC）。 X 射线光电子能谱 (XPS) 证实了 SnSe 纳米片上天然 SnO 皮的存在。 SnO/SnSe 纳米片的 Au 纳米颗粒（~3.4 nm）功能化后，负光响应得到显着改善。 Au-SnO/SnSe 在可见光和近红外光强度为 50 µW/cm 的情况下，在 10 V 偏压下分别表现出 47.55 mA/W & 1.49 × 10 Jones 和 47.8 mA/W &1.5 × 10 Jones 的响应度/探测度， NIR 曝光中的下降时间更快，分别为 841 µs 和 791 µs。 SnSe 中 NPC 的起源归因于环境空气中氧的表面吸附捕获光生热载流子。 Au 纳米颗粒在 SnO/SnSe 上功能化后，由于暗电流（以及 I/I）显着增加，NPC 进一步增加。