2019-01-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/652925摘要：隨著材料的尺度縮減，異質結構的特性將由異質介面所主導。近年來，隨著二維材料的蓬勃發展，二維異質結構的介面科學逐漸顯著重要。在二維原子層異質接面材料中，可以分為平面接合的單層異質結構與垂直疊合的層狀堆疊異質結構方式。藉由可調控二維材料介面處不同原子之接合，因不同材料之間的晶格、電荷、軌域與自旋自由度互相耦合之行為，導致介面處產生更豐富的電、光，與磁性的傳輸特性。這些新穎介面特性將成為新世代積體元件具有高度潛力的重要材料。因此，本計畫擬利用剖面掃描穿隧顯微鏡的獨特量測能力，探討新穎二維異質結構介面處之自旋/電子傳輸行為。 執行本計畫，將依介面處豐富的電、光，與磁性，討論二維異質結構介面處之四大議題： (1)探討二維異質結構介面處，材料之間因晶格不同，晶格不匹配如何影響二維異質介面上的電子態。 (2)探討二維異質結構介面處，材料之間因晶格不同，不可避免的缺陷之產生如何影響二維異質介面上的電子態。 (3)光照二維異質結構下，探討新穎二維異質介面處之載子產生、傳輸行為，以及異質介面處之光伏特性。 (4)探討二維異質結構介面處，新穎二維異質介面處自旋態傳輸行為。 基於申請人建立多年利用剖面掃描顯微鏡成功探討異質結構介面物質特性之經驗，本計畫中，擬將本研究儀器朝向多功能性發展和運用，亦即建立光調製剖面掃描顯微鏡以及自旋極化剖面掃描顯微鏡，直接觀察新穎異質介面電子/自旋態傳輸之行為。 <br> Abstract: Novel charge/spintransportbehaviorsat artificial heterointerfaces have been attracting extensive scientific attention in bothmaterials science and fundamental condensed matter physics. Recent success in controllingthe atomically sharp interfaces are formedin2D semiconductor transition metal dichalcogenide (TMD) monolayers. These 2D monolayer heterojunctions exhibit tunable energy band gap from the near-infrared to the visible region show great potential for future electronic and optoelectronic applications. Four main issues are concerned in this project. (1) One is the strain-induced influence on the electronic structure of 2D heterojunctions： Lattice-mismatched in-plane heterointerfaces of 2D-based heterojunctions introduce novel electronic structures via strain engineering. Thus, to provide the quantitative dependence of the bandgap on strain is a critical issue on novel 2D-based heterostructures. (2) The second one is the defect-induced influence on the electronic structure of 2D heterojunctions： Defects cannot be avoided in the fabrication process, and are now actively designed and controlled to realize desired functions. With a high spatial resolution STM result, to study a meaningful physical quantity of the charge transport behavior in sub nanometer-scale defects will be addressed in this project. (3) The third one is the photo-induced photoresponse of 2D heterojunctions via laser-modulated XSTM： 2D monolayer heterojunctions exhibit their type-II band alignment. The electronic characteristic can separate photoexcited electrons and holes in different materials through efficient interlayer charge transfer. Spatial evolution of the optoelectonic properties of the successfully synthesized vertical/lateral junction and the charge carrier transport behavior at their nanoscale junctions will be addressed in this project. (4) The four one is the symmetry-dependent interlayer spin transfer of 2D heterojunctions via spin-polarized XSTM. In vertically stacked monolayer heterojunctions, the different stacking configurations combined with the coupled spin-valley physics in monolayer TMDs further enrich the interplay of the spin physics, valley pseudospin, and layer pseudospin. To characterize the localized spin physicsat the interface of 2D monolayer heterojunctions will be discussed in this project. In this proposal, light-modulated cross-sectional scanning tunneling spectroscopy (LM-XSTS) through the measurement of surface photovoltage (SPV) enables us to evaluate the local potential at the atomic scale at the interface of 2D monolayer heterostructures. Furthermore, the XSTM techniquecombined with circularly polarized (CP) lightand the spin-polarized probe tip allowsus to characterize the localized spin dynamics and study the role of spins behaviorat the interface of 2D monolayer heterojunctions.新穎二維異質介面晶格不匹配缺陷光伏特性電子/自旋傳輸行為光調製/自旋極化剖面掃描顯微鏡2D monolayer heterojunctionsstrainsurface photovoltagespin transferlight-modulated XSTMmeasurement