【作者】 王颖；

【导师】 李宏建； 代国章；

【作者基本信息】 中南大学 ， 工程硕士（专业学位）， 2024， 硕士

【摘要】 第三代半导体SiC由于其宽带隙、高导热及高饱和电子漂移速率等特点被广泛应用于制造耐高温器件及光电器件。本文采用微环境调控的化学气相沉积法（CVD）,在Si/SiO₂基底上成功制备出了3C-SiC的纳米线（NWs）和微晶（MCs）两种微结构薄膜,重点研究了两种3C-SiC微结构与光电探测器性能之间的构效关系。在此基础上,进一步构建SiC/MoS₂异质结光电探测器,对其性能和工作机制进行探究。本论文主要研究内容和结果如下:（1）通过CVD法在Si/SiO₂基底上成功制备出了NWs和MCs两种微结构的SiC薄膜,对比了SiC NWs薄膜与SiC MCs薄膜之间的微结构差异,以及不同SiC微结构与光电探测器性能之间的关系。结果表明,在室温下,基于SiC NWs薄膜的光电探测器对不同波长的光分别表现为正负光电导。实现了通过温度调控SiC NWs薄膜光电探测器的正负光电导转换,最大光响应度达到了753A/W。基于SiC MCs薄膜的光电探测器在室温下表现为正光电导,升高温度后仍保持为正光电导,最大光响应度达到了1.79 m A/W。SiC NWs中负光电导的主要原因是较低温度下所生长的SiC NWs中的缺陷态捕获使载流子浓度下降,从而导致光电流低于暗电流。（2）异质结构能够有效提升电子和空穴的分离率,从而增强单个材料的光电性能。因此,进一步采用CVD法在SiC NWs薄膜上生长MoS₂,成功制备了SiC NWs/MoS₂异质结及其光电探测器。对比了SiC NWs/MoS₂异质结光电探测器和SiC NWs光电探测器的性能。结果表明,SiC NWs/MoS₂异质结光电探测器的光电流为SiC NWs光电探测器光电流的2.2倍,SiC NWs/MoS₂异质结光电探测器比纯SiC NWs光电探测器表现出更优异的光电性能。本文包含图35幅,表格4个,参考文献120篇更多还原

【Abstract】 The third-generation semiconductor SiC is widely used in the manufacture of high temperature resistant devices and optoelectronic devices because of its wide band gap,high thermal conductivity,and high saturation electron rate.In this thesis,nanowires（NWs）and microcrystals（MCs）of 3C-SiC were successfully prepared on Si/SiO₂substrate by microenvironment controlled chemical vapor deposition（CVD）.The structure-activity relationship between the two 3C-SiC microstructures and the performance of photodetectors was studied.On this basis,the SiC/MoS₂heterojunction photodetector is further constructed,and its performance and working mechanism are explored.The main research contents and results of this thesis are as follows:（1）Two kinds of SiC films of NWs and MCs were successfully prepared on Si/SiO₂substrate by CVD method.The difference of microstructure between SiC NWs films and SiC MCs films and the relationship between different SiC microstructure and the performance of photodetectors were compared.The results show that the photodetectors based on SiC NWs films exhibit positive and negative photoconductance to different wavelengths of light at room temperature.The positive and negative photoconductivity conversion of SiC NWs thin film photodetector by temperature control is realized.The maximum optical responsivity reached 753A/W.The photodetectors based on SiC MCs films show positive photoconductivity at room temperature and maintain positive photoconductivity after increasing the temperature.The maximum optical responsivity reached 1.79 m A/W.The main reason for the negative photoconductivity in SiC NWs is that the defect state trapping in SiC NWs at lower temperature reduces the carrier concentration,resulting in lower photocurrent than dark current.（2）Heterojunction structure can effectively improve the separation rate of electrons and holes,thus enhancing the photoelectric performance of a single material.Therefore,MoS₂is further grown on SiC NWs films by CVD method,SiC NWs/MoS₂heterojunction and its photodetector are successfully prepared.The performance of SiC NWs/MoS₂heterojunction photodetector and SiC NWs photodetector is compared.The results show that the photocurrent of SiC NWs/MoS₂heterojunction photodetector is 2.2 times that of SiC NWs photodetector,and the SiC NWs/MoS₂heterojunction photodetector has better photoelectric performance than pure SiC NWs photodetector.更多还原