| 摘要: | 二維材料加速發展，過渡金屬硫族化合物(TMDs)被視為最有前瞻性的二維材料，且以二硫化鉬(MoS2)發展最為快速。對MoS2而言，接觸電阻是元件電性表現的關鍵因素，當金屬沉積於MoS2時，可能會產生應變或反應，甚至還有可能造成破壞，並且接觸時會引起費米能接釘札(Fermi-level pinning)，使電性受到限制。為了觀察沉積金屬後的變化，我們將單層MoS2透過聚甲基丙烯酸甲酯(PMMA)以濕式轉印法移至二氧化矽(SiO2)上，並利用電子束蒸鍍(E-gun evaporation)與熱蒸鍍(Thermal evaporation)將金屬沉積於MoS2上，並透過拉曼光譜、X光光電子能譜、X光繞射儀、掃描式及穿透式電子顯微鏡進行分析。我們觀察到鈦、鎳、銀與金會對MoS2造成不同程度的損傷；銦、錫與鉍對MoS2僅造成微量應變，因此銦、錫與鉍較適合作為接觸金屬。另外，本研究發現鉍在MoS2上有不同的晶格取向，因為受MoS2缺陷所導致。;Recently, the development of two-dimensional materials has been accelerated. Among the two-dimensional materials, transition metal dichalocogenides(TMDs) are regarded as the most forward-looking ones, and of which molybdenum disulfide(MoS2) develops the fastest. For MoS2, the performances in electronics of its applications are limited by metal contacts, which may cause strains, chemical reactions, or even damages to MoS2. Moreover, metal contacts will cause Fermi-level pinning limiting the electrical properties. In order to observe the effects after depositing metals, we transfer MoS2 to silicon oxide(SiO2) using a polymethyl methacrylate(PMMA)-assisted wet transfer method, and then deposit metals on the monolayer MoS2 by the electron beam evaporation system and the thermal evaporation system. We analyze the properties of samples by Raman spectroscopy, X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscopy(TEM). We uncover that Ti, Ni, Ag and Au cause different levels of damage to MoS2; In, Sn and Bi only produce a small amount of strain, so In, Sn, Bi are more suitable as contact metals. In addition, Bi has different lattice orientations on MoS2. |
