The effect of the PbI $$_2$$ surface passivation on the leakage current for MAPbI $$_3$$ single crystal nuclear detectors

In semiconductor radiation detectors, leakage current is a major noise source affecting energy resolution and sensitivity. The surface passivation technology can reduce this leakage current and hence significantly enhance detector performance. Here, we demonstrate a facile way to passivate the surface of the nuclear detectors based on Methylammonium Lead Iodide (MAPbI \(_3\) ) single crystals using soaking treatment in ethanol. A dense passivation layer of PbI \(_2\) was formed on the crystal surface, significantly reducing the surface leakage current by an order of magnitude under the same voltage. The energy resolution of the MAPbI \(_3\) -based detector is therefore improved by nearly 10% for the detection of 59.5 KeV irradiated from \(^{241}\) Am. Therefore, the PbI \(_2\) passivation by ethanol-soaking treatment is proved to be an effective method to reduce leakage current and improve detection performance.