我們的實驗可以分成兩個部份。第一個部份為低溫下量子點接觸的電流電壓曲線的研究，我們量測到在零偏壓附近電阻被閘極調變而形成量子化的現象，在比較高偏壓下我們量測到電導與閘極相關的非線性曲線，並針對電導與偏壓之間的關係做一個分析，且試著找出平行磁場對電導的影響。第二部份中，我們利用磁性材料作為自旋電子的注入半導體與偵測的電極，我們的目標是藉由這個方法得知電子自旋注入的效率與遲豫的時間。

In this thesis, we report two sets of experiments. In the first set, current-voltage (IV) characteristics of a two-dimensional electron gas (2DEG) quantum point contact with ferromagnetic gate electrode were studied. Quantization of the zero bias conductance was observed in both zero field and in parallel magnetic field up to 0.3 Tesla. At finite bias voltages, the IV characteristics were nonlinear and plateaus at differential conductance versus bias voltage curves were observed. In the second set of the experiment, spin injection into 2DEG via two oppositely pointed ferromagnetic leads with Schottky-type contacts was studied. Hysteretic magnetoresistance was obtained, indicating existence of anti-parallel magnetization.

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