| 摘要: | 當系統尺寸變小，系統中電子態將變得離散，而它的物性也將跟著被調變。一般稱這現象為量子尺寸效應。量子尺寸效應雖然有趣，但因為它的效應小而經常被忽視。然而，隨著製造技術的進步，可供研究的系統尺寸已小到奈米範圍，而量子尺寸效應已不能再被忽略。量子尺寸效應的來源一直是個有趣的課題。一般相信量子尺寸效應源自於電子受到侷限。雖然許多理論工作已被完成，但由於樣品準備困難，量子尺寸效應存在的實驗證據仍然稀少。近來所長成的原子級平坦金屬薄膜已被證實是研究量子尺寸效應理想的對象。透過研究這類高度簡化系統已有許多成就。然而，許多工作仍深具挑戰性。研究奈米結構最重要的工作之一是利用量子尺寸效應來量身訂做奈米結構以符合特別的需求。本計劃將試著探討這個問題。本計劃提議使用量子尺寸效應來探索及操作如薄膜、細線、及粒子堆等奈米結構的物性。我們計劃透過自組程序有效率地建構奈米結構，並透過改變它們的尺寸、表面、及和基板間的介面來調變它們的物性。我們將使用光子協助可變溫的電子掃描穿隧顯微術來取得表面結構與動力的資料，並使用角度解析光電子能譜術來研究奈米結構中量子化的電子態。透過我們的實驗，我們預期能增進使用量子尺寸效應改變奈米結構物性的能力。這能力將在建構新穎且耐用奈米元件的過程中扮演重要的角色。 ; When the size of a system decreases, its continuous electronic states will become discrete, and its physical properties will be modulated, accordingly. It is known as the quantum size effect. The quantum size effect is interesting but often overlooked because of its relatively small contribution. However, as manufacturing technologies advancing, the size of the systems available for study has decreased into the nanometer range, and the quantum size effect can no longer be ignored. The origin of the quantum size effect has always been an interesting topic. It is generally believed that the quantum size effect results from the confinement of electrons. Although many theoretical works have been done, convincing experimental evidences for the existence of the quantum size effect were rare due to the difficulties of sample preparation. Recently, atomically flat metallic thin films were grown and have been proven to be ideal candidates for the study of the quantum size effect. Lots of successes were achieved in studying these highly simplified systems. However, many tasks remain challenging. One of the most important tasks is to use the quantum size effect to tailor the physical properties of nanostructures in order to meet special needs. Our project is aimed to address the issue. We propose to investigate and manipulate physical properties of nanostructures, such as thin films, narrow wires, and clusters, etc., with the utilizing the quantum size effect. We plan to construct nanostructures efficiently through self-organized processes, and modulate their physical properties by changing their size, surface, and interface to the substrate. We plan to employ photon-assisted variable -temperature scanning tunneling microscopy to gather the information of surface structure and dynamics, and use angle-resolved photoelectron spectroscopy to study the quantization of the electronic states in nanostructures. Through our experiments, we expect to gain insight into the dynamics related to the growth of nanostructure, and improve the ability to vary the physical properties of nanostructures by the quantum size effect in a systematical way. This ability will be the key step to construct novel and robust nanometer-size devices. ; 研究期間 9708 ~ 9807 |
