在低溫高磁場的環境下量測 III - V 族半導體氮化銦 (InN) 的電性，成長方式是用分子束磊晶系統 (Molecular Beam Epitaxy, MBE)，以四點量測通過固定電流在為外加磁場下發現氮化銦在 2.5 K 電阻率急遽下降的現象，並在 2 K $sim$ 4 K 之間每 0.25 K 做一次電阻率隨磁場變化的曲線，觀察其超導與非超導狀態下受磁場影響的轉變。再以五點霍爾量測方法量測氮化銦在磁場下的變化，霍爾電壓並非與磁場成正比，顯示氮化銦為不只是半導體而是有磁性的半導體，在高磁場可看出磁化強度 (magnetization) 已飽和 (saturation)，磁化強度以不隨磁變化，因此可通過計算把實際的霍爾電阻率 $
ho_{0}$ 與磁化強度產生的霍爾電阻 $
ho_{M}$ 分別求出，藉此可看出氮化銦為反磁性材料，最後並可算出氮化銦未受磁化強度 (magnetization) 影響的載子濃度 (carrier concentration)。

The electrical conductivity of InN, group III-V semiconductor, is measured by four point measurement at low temperatures and high magnetic fields. From Resistance Vs temperature measurements (done in the absence of magnetic field) there is a transition from semiconducting state to superconducting state at 2.5K. This superconducting state disappears when the measurements are repeated but at a magnetic field of 0.1 Tesla. Mover the Hall voltage is not proportional to the magnetic field.

1 簡介1
2 氮化銦的電性性質3
2.1 超導性質. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 2DEG 的表面電荷. . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3 氮化銦載子的性質. . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 磁電流效應(GALVANOMAGNETIC EFFECT) 5
3.1 非磁性材料. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1 一般霍爾效應(Ordinary Hall Effect) . . . . . . . . . . . 5
3.1.2 磁阻(Magnetoresistance) . . . . . . . . . . . . . . . . . 6
3.2 磁性材料. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.1 鐵磁性材料的磁電流效應. . . . . . . . . . . . . . . . . . 7
3.2.2 異常霍爾效應(Anomalous Hall Effect) . . . . . . . . . . 7
4 實驗方法與原理9
4.1 低溫高磁場環境. . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2 接線方法. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.1 歐姆接觸(ohmic contact) . . . . . . . . . . . . . . . . . 10
4.2.2 四點量測接線. . . . . . . . . . . . . . . . . . . . . . . . 11
4.2.3 五點霍爾量測接線. . . . . . . . . . . . . . . . . . . . . . 12
5 結果與討論15
5.1 氮化銦隨溫度的電阻變化. . . . . . . . . . . . . . . . . . . . . . 15
5.2 氮化銦隨磁場的電阻變化. . . . . . . . . . . . . . . . . . . . . . 21
5.3 氮化銦的異常霍爾效應. . . . . . . . . . . . . . . . . . . . . . . 22
5.4 未受磁化強度影響的氮化銦之載子濃度. . . . . . . . . . . . . . 27
文獻...........................33

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