Mobility-limiting mechanisms in polar semiconductor heterostructures
Mobility-limiting mechanisms in polar semiconductor heterostructures
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DOI：
10.1016/j.actamat.2012.02.025
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发表时间：
2012-04-01
期刊：
影响因子：
9.4
通讯作者：
Kneissl, Michael
中科院分区：
文献类型：
--
作者：
Pandey, Saurabh;Cavalcoli, Daniela;Kneissl, Michael
分析了超薄极性半导体异质结构（例如 III-V 氮化物）中二维电子气 (2DEG) 载流子迁移率的控制机制。研究了具有不同 AlN 层厚度的 InxAl1-xN/AlN/GaN 异质结构。由于可以通过改变 In 成分来调节应变，因此这些结构可以被认为是分析 III-V 族氮化物的非常好的基准。为了确定迁移率的估计值，计算了带电位错和远程表面粗糙度散射寿命。原子力显微镜和扫描隧道显微镜分析已用于测量寿命计算所需的参数，例如表面粗糙度、相关长度和位错密度，因此无需对这些参数值进行任何先验假设即可计算出总迁移率。通过霍尔效应在室温和液氮温度下测量了 InxAl1-xN/AlN/GaN 异质结构的迁移率。通过比较计算的迁移率和霍尔效应测量的迁移率，我们可以在不使用任何临时假设或拟合参数的情况下确定，远程表面粗糙度是控制低温下氮化物基异质结构中 2DEG 传输特性的最有效因素。 (C) 2012 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
The mechanisms controlling the carrier mobility of two-dimensional electron gases (2DEGs) in ultrathin polar semiconductor heterostructures, such as III-V nitrides, have been analyzed. InxAl1-xN/AlN/GaN heterostructures with different AlN layer thicknesses have been investigated. These structures can be considered a very good benchmark for the analyses of III-V nitrides, due to the possibility of modulating the strain by varying the In composition. In order to determine an estimate of the mobility, charged dislocation and remote surface roughness scattering lifetimes have been calculated. Atomic force microscopy and scanning tunneling microscopy analyses have been used to measure the parameters required for the lifetime calculation, such as surface roughness, correlation length and dislocation density, and the total mobility has thus been calculated without the need of any a priori assumptions on the values of these parameters. The mobility of InxAl1-xN/AlN/GaN heterostructures has been measured at room temperature and liquid nitrogen temperature by the Hall effect. A comparison between the calculated and the Hall-effect-measured mobilities allowed us to establish, without using any ad hoc assumptions or fitting parameters, that the remote surface roughness is the most effective factor in controlling the transport properties of 2DEGs in nitride-based heterostructures at low temperature. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.