Quantum and transport lifetimes in a tunable low-density AlGaN∕GaN two-dimensional electron gas
Quantum and transport lifetimes in a tunable low-density AlGaN∕GaN two-dimensional electron gas
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可调谐低密度 AlGaN∕GaN 二维电子气中的量子寿命和输运寿命
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
J. Caissie
中科院分区：
文献类型：
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作者：
M. Manfra;S. Simon;K. Baldwin;A. Sergent;K. West;R. Molnar;J. Caissie
我们实验确定的输运寿命（τt）的密度依赖性获得低场霍尔测量和量子寿命（τq）来自于分析的Shubnikov-de哈斯振荡的振幅在可调高迁移率二维电子气（2DEG）在Al 0.06Ga 0.94 N的scinGaN异质结。使用绝缘栅结构，我们能够将2DEG密度从2×1011调整到2× 1012 cm −2，从而在T=0.3K的单个样品中监测散射时间的演变。输运寿命τt是电子密度的强函数，从ne=2× 1011 cm −2时的2.7ps增加到ne=1.75× 1012 cm −2时的1.11ps。相反，我们发现量子散射时间τq在这个范围内对电子密度的变化相对不敏感。这些数据表明，位错散射占的密度依赖性τq以及τt在我们的低密度样品。
We experimentally determine the density dependence of the transport lifetime (τt) obtained from low-field Hall measurements and the quantum lifetime (τq) derived from analysis of the amplitude of Shubnikov–de Haas oscillations in a tunable high mobility two-dimensional electron gas (2DEG) in a Al0.06Ga0.94N∕GaN heterostructure. Using an insulated gate structure, we are able to tune the 2DEG density from 2×1011 to 2×1012cm−2, and thus, monitor the evolution of the scattering times in a single sample at T=0.3K in a previously unexplored density regime. The transport lifetime τt is a strong function of electron density, increasing from ∼2.7ps at ne=2×1011cm−2 to ∼11ps at ne=1.75×1012cm−2. Conversely, we find that the quantum scattering time τq is relatively insensitive to changes in electron density over this range. The data suggest that dislocation scattering accounts for the density dependence of τq as well as τt in our low-density sample.