Lv Quanjiang, Li Rongfan, Fan Liangchao, Huang Zhi, Huan Zhenyu, Yu Mingyang, Li Haohua, Liu Guiwu, Qiao Guanjun, Liu Junlin
School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China.
Key Laboratory for Theory and Technology of Intelligent Agricultural Machinery and Equipment, Jiangsu University, Zhenjiang 212013, China.
Sensors (Basel). 2023 Oct 12;23(20):8413. doi: 10.3390/s23208413.
PbS films grown on quartz substrates by the chemical bath deposition method were annealed in an O atmosphere to investigate the role of oxygen in the sensitization process at different annealing temperatures. The average grain size of the PbS films gradually increased as the annealing temperature increased from 400 °C to 700 °C. At an annealing temperature of 650 °C, the photoresponsivity and detectivity reached 1.67 A W and 1.22 × 10 cm Hz W, respectively. The role of oxides in the sensitization process was analyzed in combination with X-ray diffraction and scanning electron microscopy results, and a three-dimensional network model of the sensitization mechanism of PbS films was proposed. During the annealing process, O functioned as a p-type impurity, forming p-type PbS layers with high hole concentrations on the surface and between the PbS grains. As annealing proceeds, the p-type PbS layers at the grain boundaries interconnect to form a three-dimensional network structure of hole transport channels, while the unoxidized p-type PbS layers act as electron transport channels. Under bias, photogenerated electron-hole pairs were efficiently separated by the formed p-p charge separation junction, thereby reducing electron-hole recombination and facilitating a higher infrared response.
采用化学浴沉积法在石英衬底上生长的硫化铅薄膜在氧气气氛中进行退火处理，以研究在不同退火温度下氧气在敏化过程中的作用。随着退火温度从400℃升高到700℃，硫化铅薄膜的平均晶粒尺寸逐渐增大。在650℃的退火温度下，光响应度和探测率分别达到1.67 A/W和1.22×10¹¹ cm Hz¹/² W⁻¹。结合X射线衍射和扫描电子显微镜结果分析了氧化物在敏化过程中的作用，并提出了硫化铅薄膜敏化机制的三维网络模型。在退火过程中，氧气起到p型杂质的作用，在表面和硫化铅晶粒之间形成具有高空穴浓度的p型硫化铅层。随着退火的进行，晶界处的p型硫化铅层相互连接形成空穴传输通道的三维网络结构，而未氧化的p型硫化铅层则作为电子传输通道。在偏压下，光生电子-空穴对通过形成的p-p电荷分离结有效地分离，从而减少电子-空穴复合并促进更高的红外响应。
