Heterogeneously-Grown Tunable Tensile Strained Germanium on Silicon for Photonic Devices
Heterogeneously-Grown Tunable Tensile Strained Germanium on Silicon for Photonic Devices
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DOI：
10.1021/acsami.5b07385
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发表时间：
2015-12-09
影响因子：
9.5
通讯作者：
Hudait, Mantu K.
中科院分区：
文献类型：
--
作者：
Clavel, Michael;Saladukha, Dzianis;Hudait, Mantu K.
首次研究了在硅(Si)上异质集成的拉伸应变Ge(epsilon-Ge)外延层的生长、结构和光学性质以及能带排列。采用固体源分子束外延生长的InxGa1-xAs/GaAs复合线性梯度缓冲结构，获得了可调谐的epsilon-Ge薄膜。高分辨率X射线衍射和显微拉曼光谱分析证实了一种假象的epsilon-Ge外延，应变程度随InxGa1-xAs缓冲铟合金成分的变化而变化。通过横截面的详细应变分析，证实了每个epsilon-Ge外延层与各自的InxGa1-xAs应变模板之间的尖锐的异质界面。低温微区光致发光测量证实了Ge的伽马谷和L谷之间存在直接和间接的带隙辐射复合到光空穴价带，0.82+/-0.06%和1.11+/-0.03%应变Ge在Si上的L-LH型带隙分别为0.68和0.65 eV。对于epsilon-Ge/In0.11Ga0.89As(0.82%)和epsilon-Ge/In0.17Ga0.83As(1.11%)异质结，其I类能带排列和价带偏移量分别为0.27 eV和0.29 eV，显示了eSiLon-Ge载流子限制在未来纳米光电子器件中的应用前景。因此，可调谐拉伸应变Ge在Si上异质集成的成功为在Si工艺平台上设计和实现新型的Ge基光子器件铺平了道路。
The growth, structural and optical properties, and energy band alignments of tensile-strained germanium (epsilon-Ge) epilayers heterogeneously integrated on silicon (Si) were demonstrated for the first time. The tunable epsilon-Ge thin films were achieved using a composite linearly graded InxGa1-xAs/GaAs buffer architecture grown via solid source molecular beam epitaxy. High-resolution X-ray diffraction and micro-Raman spectroscopic analysis confirmed a pseudomorphic epsilon-Ge epitaxy whereby the degree of strain varied as a function of the InxGa1-xAs buffer indium alloy composition. Sharp heterointerfaces between each epsilon-Ge epilayer and the respective InxGa1-xAs strain template were confirmed by detailed strain analysis using cross-sectional transmission electron microscopy. Low-temperature microphotoluminescence measurements confirmed both direct and indirect bandgap radiative recombination between the Gamma and L valleys of Ge to the light-hole valence band, with L-lh bandgaps of 0.68 and 0.65 eV demonstrated for the 0.82 +/- 0.06% and 1.11 +/- 0.03% strained Ge on Si, respectively. Type-I band alignments and valence band offsets of 0.27 and 0.29 eV for the epsilon-Ge/In0.11Ga0.89As (0.82%) and epsilon-Ge/In0.17Ga0.83As (1.11%) heterointerfaces, respectively, show promise for epsilon-Ge carrier confinement in future nanoscale optoelectronic devices. Therefore, the successful heterogeneous integration of tunable tensile-strained Ge on Si paves the way for the design and implementation of novel Ge-based photonic devices on the Si technology platform.