Terahertz intersublevel transitions in single self-assembled InAs quantum dots with variable electron numbers.
Terahertz intersublevel transitions in single self-assembled InAs quantum dots with variable electron numbers.
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DOI：
10.1021/nl5042319
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发表时间：
2014-07
期刊：
影响因子：
10.8
通讯作者：
Ya Zhang;K. Shibata;N. Nagai;C. Ndebeka-Bandou;G. Bastard;K. Hirakawa
中科院分区：
文献类型：
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作者：
Ya Zhang;K. Shibata;N. Nagai;C. Ndebeka-Bandou;G. Bastard;K. Hirakawa
提出了一种利用金属纳米间隙电极对纳米尺度系统进行太赫兹光谱测量的方法。采用单电子晶体管结构作为太赫兹探测器，测量了单个自组装InAs量子点（QD）的次能级间跃迁光谱，获得了高信噪比的结果.光电流的库仑菱形分布表明，有两种机制的光电流产生。当p壳层被完全占据时，我们观察到由p → d跃迁引起的相当简单的光电流谱。然而，当p壳层被半填充时，光电流谱表现出明显不同的行为，我们将其归因于当空p态从电极被填充回来时电子构型的波动。
We propose a method for performing terahertz spectroscopy on nanometer (nm)-scale systems by using metal nanogap electrodes. Intersublevel transition spectra of single self-assembled InAs quantum dots (QDs) have been measured with high signal/noise ratios by using a single electron transistor geometry that consists of a QD and nanogap metal electrodes as a terahertz detector. Photocurrent distribution with respect to the Coulomb diamonds indicates that there are two mechanisms for the photocurrent generation. When the p shell was fully occupied, we observed rather simple photocurrent spectra induced by the p → d transitions. However, when the p shell was half-filled, the photocurrent spectra exhibited a markedly different behavior, which we attribute to the fluctuation in electron configuration when the empty p state is filled back from the electrodes.