在低溫下二維砷化鉀電子系統加熱電子之研究

Studies of electron heating in GaAs two-dimensional electron systems at low temperatures

陳柏中(Po-Zhung Chen)

指導教授 ： 梁啟德

國立臺灣大學/理學院/物理研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.00857

摘要

1.低溫下砷化鎵加熱電子和能量散失率之研究

最近，在低溫下砷化鎵/砷化鋁鎵異質結構二維電子傳輸的研究，可做到電子系統遷移率超過10的5次方cm/Vs。在液氦的溫度下，幾個不同輸入電流下，去測電阻，可用SdH的振幅去決定電子溫度。在這項工作中，我們會證明加熱系統，它在外加電流下，電場會正比於Te3-TL3，其中TL是晶格溫度，對於固定的電流下，電子溫度會隨著增加磁場而增加。最後，我們發現在不同的磁場下，電子溫度正比於電流的0.52次方，這跟最近研究電阻峰值變寬得到相同的結果。

2.低溫下在量子霍爾區域中砷化鎵砷化鋁鎵異質結構加熱電子之研究

當增加磁場使得相同的藍道能階分開成上旋跟下旋的磁場範圍下，我們將處理相同的物理特性，加熱電子。在填充數為三、五、七和十一時，縱向電阻的最小值會遵守反應能量方程式，用反應能量的方程式我們可以得到電子溫度，而且也發現在電流大於10的-9次方安陪情況下，會遵守幕次定律。最後在奇數的填充數下，電子溫度正比於電流的0.45次方，從遷移率的能階也可以獲得等效g常數，它會比在貞空的值(0.44)會超過的很多。等效g常數由遷移率的能階得到是8.6，此超過單一粒子的則曼能量。

關鍵字

加熱電子

並列摘要

1. Studies of electron heating in a GaAs/AlxGa1-xAs heterostructure at low temperatures

In recent studies of two-dimensional electron transport at low temperature in GaAs/AlGaAs heterojunctions one normally investigates degenerate electron systems with mobilities which can exceed 10^5cm^2/Vs. At liquid helium temperatures, the only technique that has successfully been used to determine the electron temperature of hot electron at heterojunctions is using the amplitude of Shubnikov-de Haas (SdH) oscillations in the resistivity subjected to various applying currents I. In this work, we shall show that in our system joule heating E^2 is proportional to Te^3-TL^3 where TL is the lattice temperature and E is the applying electric fields. It is interesting to note that for a fixed heating current I, Te appears to increase with increasing magnetic field B. Finally we find that Te ~ I^(0.52) at various B, in good agreement with recent experimental work on broadening of the resistivity peaks.

2. Studies of electron heating of GaAs/AlxGa1-xAs heterostructure in QH regime at low temperatures

We will treat the same physics properties of heating electron in different magnetic fields range, which is enough to separate spin up and down in Landan levels as increasing magnetic fields. At filling factors 3, 5, 7, and 11, the behavior of minimum longitudinal resistivity obey the equation of activation energy, So we can derive Te using the activation equation, and also find the power law behavior at I > 10^(-9)A in those ranges. Finally we find that Te ~ I^(0.45) at odd-integer filling factor. From the mobility gas.

並列關鍵字

electron heating

參考文獻

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