本研究以化學氣相傳輸法（CVT）成長不同釩濃度之 VxW1-xSe2（x = 0.002、0.003、0.005）單晶塊材，經機械剝離與乾式轉印製備二至四層薄片，並以電子束微影製程製作背閘極場效電晶體，系統性探討釩摻雜濃度與層數對二硒化鎢內載子傳輸特性之共同影響。材料分析方面，原子力顯微鏡 (Atomic force microscope,AFM) 的階高量測結合退火實驗顯示，表觀厚度之偏高主要源自薄片與基板間之界面吸附物，並釐清界面與層間吸附物對退火條件之不同要求；STEM-EDS 確認釩成功摻雜入二硒化鎢之晶格，但是各樣品名目濃度之實測釩含量輕度重疊，構成電性與摻雜濃度之相依性較不明顯；選區電子繞射 (select area electron diffraction, SAED) 則確認摻雜後晶體仍維持六方單晶結構，顯示釩摻雜對二硒化鎢之晶格並沒有造成破壞。
電性量測方面，所有元件均呈表觀n型導通。本研究論證此為金屬－半導體接觸之費米能階釘扎所致之注入不對稱，而非通道摻雜極性之反映，並據此確立以臨界電壓(Vth)偏移作為摻雜效應之判定指標。室溫比較顯示：層數增加使歸一化導通電流(normalized on current)上升，與能隙隨層數減小、注入位障降低這個物理機制有相同結果。摻雜元件之歸一化導通電流較未摻雜元件低約一至一個半數量級，且臨界電壓一致向正方向偏移，二者分屬輸運與靜電之獨立指標而同向吻合，構成釩受體（p型）摻雜之一致證據；摻雜元件間之參數順序則落於 EDS 成分重疊與元件變異範圍內，故穩健結論為摻雜與未摻雜之對比。變溫量測（10 – 60 K）顯示導通電流與通道電阻呈半導體式溫度相依性，次臨界擺幅未遵循預期之溫度相依性隨溫度上升而上升，與摻雜及缺陷引入局域態、低溫傳輸由熱激發傳輸主導之圖像一致。本研究建立之雙參數分析框架與以接觸物理為樞紐之極性判定方法，為未來釩摻雜之二硒化鎢元件應用的後續研究奠定基礎。

Vanadium-doped tungsten diselenide (VₓW₁₋ₓSe₂, x = 0.002, 0.003, and 0.005) single crystals were grown by chemical vapor transport. The crystals were exfoliated into two- to four-layer flakes and fabricated into back-gated field-effect transistors. These devices enable a study of how doping concentration and layer number jointly affect carrier transport. AFM measurements with annealing experiments show that the overestimated flake thickness comes mainly from adsorbates trapped at the flake–substrate interface, and clarify the different annealing conditions needed to remove interfacial and interlayer adsorbates. STEM-EDS confirms that vanadium is incorporated into the WSe₂ lattice, but the measured vanadium contents of the three nominal concentrations overlap considerably, which constrains the electrical comparisons. SAED verifies that the hexagonal lattice of WSe₂ is preserved after doping.
All devices show apparently n-type-dominant conduction. We attribute this to injection asymmetry from Fermi-level pinning at the contacts, rather than to the channel doping polarity. The threshold-voltage shift is therefore adopted as the primary doping indicator. At room temperature, the normalized on-current increases with layer number, consistent with the lower injection barrier of thicker flakes. Doped devices show normalized on-currents one to one-and-a-half orders of magnitude below the undoped reference, together with a consistent positive threshold-voltage shift. These two independent observations provide consistent evidence of p-type doping by vanadium. Differences among the doped devices fall within the compositional overlap and device variation, so the robust conclusion is the doped-versus-undoped contrast. Measurements at 10–60 K show insulating temperature dependence and a subthreshold swing deviating from thermionic scaling, indicating that localized states dominate low-temperature transport through thermally assisted hopping. These results provide a framework for future studies of doped two-dimensional semiconductors.

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