Thermal Emission Spectra from Individual Suspended Carbon Nanotubes
Thermal Emission Spectra from Individual Suspended Carbon Nanotubes
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DOI：
10.1021/nn200444x
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发表时间：
2011-06-01
期刊：
影响因子：
17.1
通讯作者：
Cronin, Stephen B.
中科院分区：
文献类型：
--
作者：
Liu, Zuwei;Bushmaker, Adam;Cronin, Stephen B.
研究了单个悬浮碳纳米管在电加热下的热发射光谱。半导体和金属器件由于其独特的能带结构而表现出不同的光谱。将这些光谱与理想黑体发射光谱进行了比较。在可见波长范围内，半导体器件的热发射光谱符合普朗克定律，而金属器件的光谱在1.5 ~ 1.9 eV之间有一个附加峰。在近红外波长范围内，半导体纳米管表现出1 eV左右的峰值。这些额外的峰值归因于在这些高施加偏置电压下热驱动的E-11(M)和E-22（SC）跃迁。这些峰表现出较强的极化依赖性，而黑体高为非极化，这为热发射中电子空穴复合的存在提供了进一步的证据。对于半导体器件，纳米管的温度符合普朗克定律，并与G波段和2D波段拉曼降频得到的温度以及反斯托克斯/斯托克斯强度比进行了比较。对于热非平衡器件，电子温度与G（+）降移一致，但偏离G（_）降移。
We study the thermal emission spectra of Individual suspended carbon nanotubes induced by electrical heating. Semiconducting and metallic devices exhibit different spectra, based on their distinctive band structures. These spectra are compared with the ideal blackbody emission spectrum. In the visible wavelength range, the thermal emission spectra of semiconducting devices agree well with Planck's law, while the spectra of metallic devices show an additional peak between 1.5 and 1.9 eV. In the near-infrared wavelength range, the semiconducting nanotubes exhibit a peak around 1 eV. These additional peaks are attributed to the E-11(M) and E-22(SC) transitions that are thermally driven under these high applied bias voltages. These peaks show a strong polarization dependence, while the blackbody tall is unpolarized, which provides further evidence for electron hole recombination in thermal emission. For semiconducting devices, the temperature of the nanotube is fit to Planck's law and compared with the temperatures obtained from the G band and 2D band Raman downshifts, as well as the anti-Stokes/Stokes intensity ratio. For devices showing thermal non-equilibrium, the electron temperature agrees well with G(+) downshift but deviates from G(_) downshift.