Doping by chemical or physical means is key for the development of future semiconductor technologies. Ideally, charge carriers should be able to move freely in a homogeneous environment. Here, we report on evidence suggesting that excess carriers in electrochemically p-doped semiconducting single-wall carbon nanotubes (s-SWNTs) become localized, most likely due to poorly screened Coulomb interactions with counterions in the Helmholtz layer. A quantitative analysis of blue-shift, broadening, and asymmetry of the first exciton absorption band also reveals that doping leads to hard segmentation of s-SWNTs with intrinsic undoped segments being separated by randomly distributed charge puddles approximately 4 nm in width. Light absorption in these doped segments is associated with the formation of trions, spatially separated from neutral excitons. Acceleration of exciton decay in doped samples is governed by diffusive exciton transport to, and nonradiative decay at charge puddles within 3.2 ps in moderately doped s-SWNTs. The results suggest that conventional band-filling in s-SWNTs breaks down due to inhomogeneous electrochemical doping.

中文翻译：

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掺杂碳纳米管中的局部电荷控制激子能量和能量耗散

通过化学或物理方式进行掺杂是未来半导体技术发展的关键。理想情况下，电荷载体应能够在均匀的环境中自由移动。在这里，我们报告的证据表明，电化学p掺杂半导体单壁碳纳米管（s-SWNTs）中的过量载流子变得局部化，最有可能是由于与亥姆霍兹层中抗衡离子的库仑相互作用筛选不佳。对第一个激子吸收带的蓝移，展宽和不对称的定量分析还表明，掺杂会导致s-SWNT的硬分段，其固有的未掺杂链段被大约4 nm宽度的随机分布的电荷坑隔开。这些掺杂段中的光吸收与在空间上与中性激子分开的tri形成有关。掺杂样品中激子衰减的加速受扩散掺杂激子向中掺杂s-SWNT中3.2 ps内的电荷激子输运和非辐射衰变的控制。结果表明，由于不均匀的电化学掺杂，s-SWNT中的常规能带填充发生了破坏。