錳參雜硒化鉛量子點陣列之電性研究

Abstract

利用介電泳(dielectrophoresis)法將錳參雜硒化鉛量子點陣列(PbMsSe quantum-dot nanoarrays)橫跨在間隔約為兩百奈米的兩個電極上，藉由隨溫度改變而變化的電流-電壓曲線來研究此PbMnSe奈米陣列元件的電性。在低偏壓高溫區域(300 K–220 K)，此奈米陣列元件為熱活化傳輸，熱活化能約為0.2–0.4 eV；而在低偏壓低溫區域(220 K–80 K)，傳輸機制為跳躍傳導，此外也發現到PbMnSe奈米陣列根數的多寡會改變跳躍傳導的維度因子(p值)；在高偏壓低溫區域(100 K以下, 偏壓>閘值電壓)，此電流-電壓曲線可以用集體電荷傳輸(collective charge transport)理論來描述，集體傳輸的維度因子(ξ值)與PbMnSe奈米陣列根數的多寡有相關。

PbMsSe quantum-dot nanoarrays were aligned and deposited in a two-electrode nanogap by adopting dielectrophoresis technique. Electrical properties of the as-fabricated PbMnSe nanoarray devices were examined through taking temperature dependent current-voltage behaviors. We found that, in a temperature range of 220 – 300 K, the zero-bias resistance of the nanoarray devices exhibited thermally activated transport with an activation energy of about 0.2 – 0.4 eV. On the other hand, those devices revealed hopping conduction in low temperatures from 80 to 220 K. Moreover, we discovered that the number of aligned PbMnSe nanoarrays could change the dimensional factor of hopping conduction. In a bias voltage larger than a threshold voltage and at low temperature (below 100 K), the current-voltage curve agrees with the theory of collective charge transport which gives an another dimensional factor. We learned that the dimensional factors of collective transport in the nanoarray devices depend strongly on the number of aligned PbMnSe nanoarrays as well.