非常规中间带半导体BixSn1-xO2多维复合薄膜量子工程与超灵敏紫外探测器研究

The aim of this project is to fabricate intermediate band semiconductor BixSn1-xO2(0.009<x<0.09) multi-dimensional nanowires films by physical vapor deposition and lift off technology; to study the influence of fabrication parameters on the crystal structures, composites, elements chemical states of nanowires films; to establish the relationship between equivalent valence of Bi and optical and electrical properties of BixSn1-xO2 nanowires films; To construct the ultraviolet photoconductors based on BixSn1-xO2 nanowires films. The figure of merits of the UV photodetector, including spectral responsibility, detectivity, dynamic range, will be investigated under different wavelengths and bias voltages. To study the structure-performance relationship between the nanowire diameter and photodetector. To obtain a high performance BixSn1-xO2 film based-UV photodetector with responsibility more than 100 A/W, detectivity higher than 1E17 Jones and the response time less than 50 ms. The UV photodetectors have drawn considerable interests due to their ubiquitous applications in the areas like astronomical telescope, spatial secure optical communication, chemical or biological agent sensing, missile warning. Due to excellent properties, including wide bandgap (3.6 eV), large absorption coefficient (>1E5 /cm) in DUV band, high transparency in visible light range, exotic electrical properties (mobility: 13500 cm2/V•s@45K), and high physicochemical stability, the SnO2 is a promising material to construct UV photodetectors. Up to now, there is still a great challenge to actualize high detectivity photodetectors based on SnO2 through improving the photocurrent gain and decreasing the dark current density. The resolve of above challenge through intermediate band engineering in BixSn1-xO2 semiconductor is significant for both science and technology application, and will provide some basis on the development of SnO2-based UV optoelectronic devices.

紫外探测器在天文、国防、通信、遥感等领域具有重要应用。本项目拟解决SnO2基紫外探测器低暗电流密度和高响应度难以兼备的本征问题，提高器件对极弱紫外光的感测能力。采用物理气相沉积和干涉光刻技术生长非常规中间带半导体BixSn1-xO2纳米线膜(0.009<x<0.09)。通过量子调控工程，在BixSn1-xO2带隙中形成高态密度和满电子占据的非常规中间带；研究生长工艺参数对纳米线膜的微结构、元素成分和价态、光学和电学性能等影响，建立Bi化合价与纳米线膜物性之间的调控关系。设计构筑光导型紫外探测器，确定响应度，探测率，动态范围等器件性能参数随波长和器件偏压等的变化关系，获得响应度>100A/W，探测率>E17Jones，响应时间<50ms紫外探测器。研究纳米线的径向尺寸对探测器性能的影响规律，建立两者之间的构效关系。通过本项目实施，将为SnO2基超灵敏紫外探测器的发展和应用奠定基础。

高灵敏紫外探测器在天文、国防、通信、遥感等领域具有重要应用。以硅为代表的商用光探测器在紫外波段响应度很低，迫切需要发展高灵敏紫外光电探测器件。本项目主要开展以下研究：SnO2/绒面硅异质结宽谱光电探测器件；Bi掺杂SnO2准二维膜制备与紫外探测器件；基于CsPbCl3, CsPbI3和CsCu2I3高性能无机钙钛矿紫外光电探测器件；面向紫外传感-存储-运算应用的新型忆阻材料与器件。（1）通过设计不同绒面结构硅，调节器件对于光的捕获能力，实现250-1050nm范围宽谱高灵敏光探测，800nm处峰值响应度为1.88A/W，器件上升和下降时间分别为18.07和29.16毫秒。该项成果对于开发商用硅工艺兼容的光电探测器件具有一定应用价值。（2）设计Bi-Sn合金颗粒并表面热氧化，剥离获得Bi掺杂SnO2准二维膜，通过Bi掺杂在能带引入中间带，实现高性能紫外探测，300 nm峰值响应度为589 A/W。通过引入不同种还原性物质蒸汽（甲醇、乙醇、丙二醇、NaNO2、Na2SO3）的方法，能够显著加快器件恢复。该方法不但提供消除半导体PPC效应的方法；也展示了利用PPC效应实现“暗态光催化”的新现象。（3）制备CsPbI3纳米线紫外光探测器，在325nm波长响应度4.72 A/W，探测率高达1.09E14琼斯，响应时间 960和0.930 ms（4）通过水处理CsCu2I3晶体获得多孔结构，多孔结构能够显著减少晶体对紫外光的反射，提高紫外探测器件性能。在5V偏压下，360 nm和 250 nm响应度分别为0.59 A/W和0.84 A/W，器件上升和下降时间分别达到119和287毫秒。（5）开展了h-BN, 钙钛矿等忆阻材料与器件研究工作，为未来紫外光电信号探测-存储-运算一体化的发展奠定一定基础。（6）通过激光辐照Au与CuCl2，FeCl3混合溶液，利用表面等离激元产生的强氧化性“热空穴”刻蚀溶解Au。该项工作为微纳光电子器件中低成本构建超窄线宽（~10nm以下）的Au电极提供了可行性研究基础。