On the conduction mechanism in compositionally graded AlGaN
On the conduction mechanism in compositionally graded AlGaN
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DOI：
10.1063/5.0100756
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发表时间：
2022-08
影响因子：
4
通讯作者：
S. Rathkanthiwar;P. Bagheri;D. Khachariya;J. Kim;Y. Kajikawa;P. Reddy;S. Mita;R. Kirste;B. Mo
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文献类型：
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作者：
S. Rathkanthiwar;P. Bagheri;D. Khachariya;J. Kim;Y. Kajikawa;P. Reddy;S. Mita;R. Kirste;B. Mo
提出了一个两带输运模型来解释梯度铝镓氮化物层中的导电性，其中价带中的自由空穴导电在高温下是有利的，杂质带中的跳跃导电在低温下占主导地位。该模型同时解释了显着降低的活化能为p型导电（1000毫电子伏），在较低的温度（200-330 K），一个几乎恒定的薄层电导率，并在跳跃传导过程中的霍尔散射因子的负号所造成的霍尔系数的异常反转。均匀和渐变的样品之间的比较表明，组成渐变显着提高的概率声子辅助的Mg原子之间的跳跃跃迁。
A two-band transport model is proposed to explain electrical conduction in graded aluminum gallium nitride layers, where the free hole conduction in the valence band is favored at high temperatures and hopping conduction in the impurity band dominates at low temperatures. The model simultaneously explains the significantly lowered activation energy for p-type conduction (∼10 meV), a nearly constant sheet conductivity at lower temperatures (200–330 K), and the anomalous reversal of the Hall coefficient caused by the negative sign of the Hall scattering factor in the hopping conduction process. A comparison between the uniform and graded samples suggests that compositional grading significantly enhances the probability of phonon-assisted hopping transitions between the Mg atoms.