本論文主要是探討具有奈米尺寸厚度的多層二硒化鉬(MoSe2)層狀半導體(Semiconductor)撕之電傳輸特性，實驗上利用機械剝離(Mechanical Exfoliation)的方式製作不同厚度的層狀半導體，並以原子力顯微鏡(AFM)定義其厚度，使用聚焦離子束雙束系統(FIB)沈積法製作兩點與四點式電極之奈米元件。藉由電流對電壓曲線量測，發現厚度較薄的奈米層狀結構的電導率(conductivity)高於同質塊材(bulk)約三個數量級，對於厚度在788奈米厚度之多層結構，其電導率範圍大約在340-540。在統計約33個不同厚度的樣品，顯示電導率並非常數並且似乎與樣品厚度成反比關係。推測此結果樣品電導值(conductance)可能受制於較高的表面電導率，暗示這類層狀半導體奈米結構存在不均勻的塊材導電率，可能存在較高的表面導電特性。進一步地，藉由變溫暗電導量測發現在奈米尺寸的厚度下，多層二硒化鉬半導體皆具有共通的弱半導體性與極小的載子活化能（約611 meV），此結果小於數十微米的塊材樣品(約34 meV)，似乎也顯示奈米多層結構之主要載子來源不同於塊材本身，推測材料表面可能存在接近導電帶底端之表面態缺陷。

The electronic transport properties of the molybdenum diselenide (MoSe2) layer semiconductor with nanometer and micrometer –thicknesses have been investigated. It is found that the very thin multilayer MoSe2 with thickness at 788 nm exhibit much higher average conductivity at 440100 S/cm, which is over three orders of magnitude higher than the bulk counterparts. The statistic conductivity values showing significant thickness dependence are also observed. In addition, by the temperature-dependent measurement, the nanometer-thick MoSe2 layer crystals reveal weak semiconducting behavior with very low activation energies at 611 meV which are relatively lower than those of the micrometer-sized samples. The potential presence of the higher surface conductivity induced by the donor-like surface states is proposed to explain the highly conductive nature and its thickness dependence in this layer semiconductor.

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