垂直型MoS2/C60范德华异质结的研究

研究了采用垂直堆垛方式构筑的MoS2/C60范德华异质结的特性。利用直流磁控溅射法制备Mo薄膜,对Mo薄膜进行硫化退火处理得到MoS2薄膜,采用真空蒸镀法在MoS2薄膜上沉积C60进而形成MoS2/C60范德华异质结,并制备了Au/MoS2/C60/Al结构的器件。对MoS2薄膜的晶体结构进行了分析,对MoS2,C60及MoS2/C60薄膜的喇曼光谱及光吸收特性进行了测试和表征。结果表明:经过750℃退火后的MoS2晶型为2H型;由于在MoS2和C60薄膜之间范德华力的存在,相对于生长在Si/SiO2衬底上,沉积在MoS2上的C60薄膜喇曼特征峰发生红移;MoS2/C60薄膜在可见光范围内具有明显的光吸收特性;异质结表现出良好的整流特性,通过电子导电模型分析得出电子的传输机制包含热电子发射,空间电荷限制电流传导(SCLC)和隧穿现象。

Study of Vertical MoS2/C60 van der Waals Heterojunction

Characteristics of van der Waals heterojunction of MoS2/C60 fabricated by vertical stacking were investigated.Mo films were prepared by DC magnetron sputtering method,and MoS2 films were formed by sulfurized and annealed in S(g) atmosphere.The C60 films were deposited on MoS2 films by vacuum evaporation,thus MoS2/C60 van der Waals heterojunction was formed.A device with Au/MoS2/C60/Al structure was prepared.The crystal structure of MoS2 film was analyzed.The Raman spectra and absorption properties of MoS2,C60 and MoS2/C60 films were tested and characterized.The results show that the crystal structure of MoS2 after annealing at 750℃ is trigonal prismatic(2H).When C60 is deposited on the MoS2 film,the Raman peak of C60 is slightly red-shifted in comparison with that deposited on Si/SiO2 substrate,due to van der Waals forces between MoS2 and C60.The MoS2/C60 film has good absorption properties in visible light range.The heterojunction shows good rectification characteristics.Through electron conduction model analysis,the transport mechanisms of the electronics include thermionic emission,space charge limited conduction(SCLC),and tunneling phenomenon.