Zheng Zhi-Yuan, Fan Ming-Ming
College of Science, Hunan University of Science and Engineering, Yongzhou 425199, People's Republic of China.
College of Physics, Taiyuan University of Technology, Taiyuan 030024, People's Republic of China.
Nanotechnology. 2024 May 23;35(32). doi: 10.1088/1361-6528/ad470e.
Herein, corundum-structured GaO(-GaO) nanorod array/fluorine-doped SnO(FTO) structures have been fabricated by hydrothermal and thermal annealing processes with different precursor concentrations from 0.01 to 0.06 M. The diameter and length of the nanorod arrays are much larger with increasing precursor concentrations due to more nucleation sites and precursor ions participating in the reaction procedures. The optical bandgap decreases from 4.75 to 4.47 eV because of the tensile stress relieving with increasing the precursor concentrations. Based on self-powered photoelectrochemical (PEC) photodetectors, the peak responsivity is improved from ∼0.33 mA Wfor 0.06 M to ∼1.51 mA Wfor 0.02 M. Schottky junctions can be formed in PEC cells. More photogenerated carriers can be produced in wider depletion region. From Mott-Schottky plots, the depletion regions become much wider with decreasing the precursor concentrations. Therefore, the enhance responsivity is owing to the wider depletion regions. Due to the reduced possibility of photogenerated holes captured by traps ascribed from fewer green and yellow luminescence defects, smaller charge transfer resistance, and shorter transportation route, the decay time becomes much faster through decreasing the precursor concentrations. Compared with the other self-powered-GaO-nanorod-array-based PEC photodetectors, it shows the fastest response time (decay time of 0.005 s/0.026 s) simply modulated by precursor concentrations for the first time without employing complex precursors, seed layers or special device designs. Compared with other high-responsivity monoclinic GaO(-GaO) self-powered photodetectors, our devices also show comparable response speed with simple control and design. This work provides the realization of fast-speed self-powered GaObased solar-blind ultraviolet photodetectors by simple modulation processes and design, which is a significant guidance for their applications in warnings, imaging, computing, communication and logic circuit, in the future.
在此，通过水热法和热退火工艺，使用浓度从0.01到0.06 M的不同前驱体，制备了刚玉结构的GaO(-GaO)纳米棒阵列/氟掺杂SnO(FTO)结构。由于更多的成核位点和前驱体离子参与反应过程，随着前驱体浓度的增加，纳米棒阵列的直径和长度显著增大。由于随着前驱体浓度增加拉伸应力得以缓解，光学带隙从4.75 eV降至4.47 eV。基于自供电光电化学(PEC)光电探测器，峰值响应率从0.06 M时的约0.33 mA W提高到0.02 M时的约1.51 mA W。在PEC电池中可形成肖特基结。在更宽的耗尽区能产生更多的光生载流子。根据莫特-肖特基曲线，随着前驱体浓度降低，耗尽区变得更宽。因此，响应率的提高归因于更宽的耗尽区。由于更少的绿色和黄色发光缺陷导致光生空穴被陷阱捕获的可能性降低、电荷转移电阻更小以及传输路径更短，通过降低前驱体浓度，衰减时间变得更快。与其他基于自供电GaO纳米棒阵列的PEC光电探测器相比，首次在不采用复杂前驱体、种子层或特殊器件设计的情况下，仅通过前驱体浓度简单调制，它就展现出最快的响应时间（衰减时间为0.005 s/0.02 s）。与其他高响应率单斜GaO(-GaO)自供电光电探测器相比，我们的器件在简单的控制和设计下也展现出相当的响应速度。这项工作通过简单的调制工艺和设计实现了高速自供电GaO基日盲紫外光电探测器，这对其未来在警告、成像计算、通信和逻辑电路中的应用具有重要指导意义。
