電壓相依穿隧率對於單電子電晶體之電荷傳輸的影響

Bias-dependent tunneling rate effects on the charge transport of single electron transistors

陳裕斌(Yu-bin Chen)

指導教授 ： 郭明庭

國立中央大學/資訊電機學院/電機工程學系/碩士(2015年)

摘要

室溫下操作的單電子電晶體，其量測電位及閘極電壓都非常大。因此穿隧率極易受應用電位及閘極電壓影響。本論文利用WKB近似來計算電壓相依的穿隧率。量子點到左、右電極的穿隧率是應用電位及閘極電壓的指數函數. 不僅如此,量子點能階、穿隧能障厚度及穿隧能障高度對於左、右穿隧率也有重要的影響。我們也發現量子點之電子佔據率深受電位相依的穿隧率影響, 穿隧電流出現類階梯的行為, 及庫倫震盪電流曲線則呈現出震盪波峰高度隨閘極電壓壓上升而升高的情況。模擬結果和實驗量測結果相當吻合.

關鍵字

單電子電晶體 ； 電壓相依穿隧率

並列摘要

The large applied bias and gate voltage of single electron transistors operated at room temperatures lead to the charge transport far away from equilibrium , therefore the tunneling rates of electrons are significantly influenced by the applied bias and gate voltage. Using WKB approximation, we calculate the bias and gate voltage-dependent electron tunneling rates. The left and right tunneling rates of a single quantum dot (QD) are the exponential function of the applied bias and gate voltage. In addition, these tunneling rates also depend on the barrier height, barrier width and QD energy levels. We find that tunneling currents show the quasi- staircase behavior and Coulomb oscillatory current with respect to gate voltage increases with increasing gate voltage. These features get very good agreement with experimental measurements.

並列關鍵字

Single electron transistor ； bias-dependent tunneling rate

參考文獻

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S. Dzurak”Observation of the single-electron regime in a highly tunable silicon