Piezoelectric actuation of (GaN/)AlGaN/GaN heterostructures
Piezoelectric actuation of (GaN/)AlGaN/GaN heterostructures
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DOI：
10.1063/1.3005885
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发表时间：
2008-10
影响因子：
3.2
通讯作者：
K. Tonisch;C. Buchheim;F. Niebelschütz;A. Schober;G. Gobsch;V. Cimalla;O. Ambacher;R. Goldhahn
中科院分区：
文献类型：
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作者：
K. Tonisch;C. Buchheim;F. Niebelschütz;A. Schober;G. Gobsch;V. Cimalla;O. Ambacher;R. Goldhahn
本文详细分析了(GaN/)AlGaN/GaN异质结的压电响应。比较了Al含量为31%的两种异质结的机电性能。对于具有薄GaN盖层的样品，只形成单一的二维电子气(2DEG)，而在厚GaN盖层的情况下，2DEG和二维空穴气体共存。较低的GaN层代表机械支撑层，而AlGaN薄膜，以及在某些情况下的附加GaN帽层，充当用于驱动的压电性有源层。2DEG(位于AlGaN/GaN的下界面处)提供导电通道，作为施加外部电压的背电极。为了确定作为施加电压的函数的整个结构上的电场分布，应用了电反射光谱。研究发现，在有源区只有部分调制电压下降。压电力显微镜产生...
A detailed analysis of the piezoelectric response of (GaN/)AlGaN/GaN heterostructures is reported. The electromechanical properties of two types of heterostructures with an Al content of 31% are compared. Only a single two-dimensional electron gas (2DEG) is formed for samples with thin GaN cap layers, while both a 2DEG and a two-dimensional hole gas coexist in the case of thick GaN caps. The lower GaN layer represents the mechanically supporting layer, while the AlGaN film, and in some cases an additional GaN cap layer, serves as the piezoelectrically active layers for actuation. The 2DEG (at the lower AlGaN/GaN interface) provides the conducting channel which was used as back electrode for the applied external voltage. Electroreflectance spectroscopy is applied in order to determine the electric field distribution across the whole structure as a function of the applied voltage. It is found that only a part of the modulation voltage drops across the active region. Piezoelectric force microscopy yields the...