AuGe surface plasmon enhances photoluminescence of the InAs/GaAs bilayer quantum dot heterostructure
AuGe surface plasmon enhances photoluminescence of the InAs/GaAs bilayer quantum dot heterostructure
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AuGe表面等离子体增强InAs/GaAs双层量子点异质结构的光致发光
DOI：
10.1039/c5ra27980a
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发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
S. Chakrabarti
中科院分区：
文献类型：
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作者：
S. Pandey;Lavi Tyagi;P. Shete;H. Ghadi;H. Rawool;Poonam Murkute;S. Chakrabarti
我们报道了在GaAs覆盖的InAs/GaAs双层量子点（QD）异质结构的光致发光的改善AuGe纳米颗粒沉积在薄的覆盖层的表面上。扫描电子显微镜证实了在300至700 °C的温度范围内表面上AuGe纳米颗粒的形成。光学吸收光谱揭示了在300 °C下退火的样品在约670 nm处的AuGe纳米颗粒的等离子体共振峰，证实了等离子体效应的存在。拉曼光谱显示，在300 °C退火的样品在238.5 cm-1处有一个量子点声子峰，表明异质结构中有InAs量子点。与未覆盖的样品相比，在300 °C和400 °C下退火的AuGe沉积样品的PL谱中观察到增强（增强因子分别为2.58和2.18）。观察到的增强归因于光子捕获的散射从偶极子辐射场的横截面。当退火温度从300 °C提高到700 °C时，In/Ga相互扩散使18 K处的光致发光峰发生蓝移。随着退火温度从300 °C增加到700 °C，观察到激活能的降低，这归因于样品表面处的限制电位差和高电子浓度。我们的研究结果有助于实现高效率的等离子体为基础的InAs量子点探测器的光通信在1300 nm的光学窗口。
We report an improvement in the photoluminescence of a GaAs-capped InAs/GaAs bilayer quantum dot (QD) heterostructure by AuGe nanoparticle deposition on the surface of a thin capped layer. Scanning electron microscopy confirmed the formation of AuGe nanoparticles on the surface at temperatures ranging from 300 to 700 °C. Optical absorption spectroscopy revealed the plasmon resonance peak of AuGe nanoparticles at around 670 nm for the sample annealed at 300 °C, confirming the presence of the plasmonic effect. Raman spectroscopy revealed a QD phonon peak at ∼238.5 cm−1 for the sample annealed at 300 °C, indicating InAs QDs in the heterostructure. Compared to the uncovered sample, enhancements were observed in the PL spectra of the AuGe-deposited samples annealed at 300 °C and 400 °C (with enhancement factors of 2.58 and 2.18, respectively). The observed enhancement is attributed to photon trapping by scattering from the cross section of the dipole radiation field. Increasing the annealing temperature from 300 °C to 700 °C blue-shifted the photoluminescence peaks at 18 K because of In/Ga inter-diffusion. A decrease in activation energy was observed with the increase in annealing temperature from 300 °C to 700 °C, attributed to poor confinement potential and high electron concentration at the sample surface. Our findings contribute to the realization of high-efficiency plasmonic-based InAs QD detectors for optical communication in the 1300 nm optical window.
DOI：
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发表时间：
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期刊：
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影响因子：
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作者：
V. Ferry;M. Verschuuren;Hongbo B T Li;E. Verhagen;R. Walters;R. Schropp;H. Atwater;A. Polman
通讯作者：
V. Ferry;M. Verschuuren;Hongbo B T Li;E. Verhagen;R. Walters;R. Schropp;H. Atwater;A. Polman