论文标题
高度双极掺杂WS2中的激子歧管
Exciton manifolds in highly ambipolar doped WS2
论文作者
论文摘要
2D半导体中单个粒子特性的分离及其对高载体浓度的依赖性对于通过纯粹的光学手段进行实验研究的挑战。我们建立了一个能够将费米水平从价值转移到适合于光学上痕迹的激子结合以及弱掺杂方案中的单个颗粒带隙能量的电解质门控单层磁场效应结构。横跨大型N和P型掺杂的光谱成像椭圆法和光致发光光谱镜结合了电荷载体密度，最高可达10^14 cm-2，可研究筛选现象和掺杂依赖于富含兴奋的兴奋性歧管的兴奋性演变，其来源在文献中引起了争议。我们表明，光致发光实验中的两个最突出的发射带是由于声子激活的自旋孔和动量 - 孔孔电荷中性激素的重组。在电子或孔掺杂下，观察到的频带间跃迁被红移，并急剧削弱。该现场效应平台不仅适合研究激子歧管，而且还适用于在低温温度下在掺杂的原子较薄的量子材料上的光学和传输测量。
The disentanglement of single and many particle properties in 2D semiconductors and their dependencies on high carrier concentration is challenging to experimentally study by pure optical means. We establish an electrolyte gated WS2 monolayer field-effect structure capable to shift the Fermi level from the valence into the conduction band suitable to optically trace exciton binding as well as the single particle band gap energies in the weakly doped regime. Combined spectroscopic imaging ellipsometry and photoluminescence spectroscopies spanning large n- and p-type doping with charge carrier densities up to 10^14 cm-2 enable to study screening phenomena and doping dependent evolution of the rich exciton manifold whose origin is controversially discussed in literature. We show that the two most prominent emission bands in photoluminescence experiments are due to the recombination of spin-forbidden and momentum-forbidden charge neutral excitons activated by phonons. The observed interband transitions are redshifted and drastically weakened under electron or hole doping. This field-effect platform is not only suitable for studying exciton manifold but is also suitable for combined optical and transport measurements on degenerately doped atomically thin quantum materials at cryogenic temperatures.
