Formation and characterization of multilayer GeSi nanowires on miscut Si (001) substrates.
Formation and characterization of multilayer GeSi nanowires on miscut Si (001) substrates.
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DOI：
10.1166/jnn.2013.5979
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发表时间：
2013-02
影响因子：
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通讯作者：
H. Gong;Peixuan Chen;Yingjie Ma;Lijun Wang;A. Rastelli;O. Schmidt;Z. Zhong
中科院分区：
文献类型：
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作者：
H. Gong;Peixuan Chen;Yingjie Ma;Lijun Wang;A. Rastelli;O. Schmidt;Z. Zhong
在错切的Si(001)衬底上，可以很容易地自组装出由Si间隔物隔开的多层GeSi纳米线，且向(110)方向倾斜8度。沿错切方向取向的纳米线非常细小，并紧密排列在邻近表面。对GeSi纳米线进行了系统的光致发光光谱研究。随着激发功率的增加，多层GeSi纳米线的光致发光强度呈次线性变化，蓝移为-7 meV/ten，光致发光峰的半高宽几乎恒定。这些结果表明GeSi纳米线/Si具有典型的III型能带排列。蓝移归因于随着光子产生的载流子的增加而产生的能带弯曲效应。近邻纳米线中空穴的强耦合形成了微带，从而解释了发光峰的半高宽与激发功率的关系。从纳米线的光致发光峰随温度变化的强度中提取了-12 meV的激活能，该激活能被指定为纳米线周围的激子结合能。基于拉曼光谱，估算出GeSi纳米线中Ge的含量为-61%。
A multilayer of GeSi nanowires separated with Si spacers was readily self-assembled on miscut Si (001) substrates with 8 degrees off toward (110). The nanowires oriented along the miscut direction were very small and compactly arranged on the vicinal surface. Systematic photoluminescence (PL) spectroscopy studies were carried out on the GeSi nanowires. With increasing excitation power, a sublinear power dependent PL intensity and a blue-shift of -7 meV/decade with nearly constant full width of half maximum (FWHM) of PL peaks from multilayer GeSi nanowires was observed. These results indicated a typical type-III band alignment of GeSi nanowires/Si. The blue-shift was attributed to band bending effect with the increase of photon-generated carriers. The nearly independent FWHM of PL peaks with the excitation power was explained in terms of the formation of mini-band due to strong coupling of holes in closely neighboring nanowires. An activation energy of -12 meV was extracted from the temperature-dependent intensity of PL peaks of the nanowires, which was assigned to be the exciton binding energy around the nanowires. Based on Raman spectra, the Ge content in GeSi nanowires was estimated to be -61%.