Laboratoire National des Champs Magnétiques Intenses, CNRS-UJF-UPS-INSA , 143, avenue de Rangueil, 31400 Toulouse, France.
Nano Lett. 2014 May 14;14(5):2807-14. doi: 10.1021/nl500818k. Epub 2014 Apr 22.
Achieving significant doping in GaAs/AlAs core/shell nanowires (NWs) is of considerable technological importance but remains a challenge due to the amphoteric behavior of the dopant atoms. Here we show that placing a narrow GaAs quantum well in the AlAs shell effectively getters residual carbon acceptors leading to an unintentional p-type doping. Magneto-optical studies of such a GaAs/AlAs core-multishell NW reveal quantum confined emission. Theoretical calculations of NW electronic structure confirm quantum confinement of carriers at the core/shell interface due to the presence of ionized carbon acceptors in the 1 nm GaAs layer in the shell. Microphotoluminescence in high magnetic field shows a clear signature of avoided crossings of the n = 0 Landau level emission line with the n = 2 Landau level TO phonon replica. The coupling is caused by the resonant hole-phonon interaction, which points to a large two-dimensional hole density in the structure.
在 GaAs/AlAs 核/壳纳米线 (NWs) 中实现显著的掺杂具有重要的技术意义，但由于掺杂原子的两性行为，这仍然是一个挑战。在这里，我们表明，在 AlAs 壳中放置一个狭窄的 GaAs 量子阱可以有效地捕获残留的碳受体，从而导致非故意的 p 型掺杂。对这种 GaAs/AlAs 核-多壳 NW 的磁光研究揭示了量子限制发射。NW 电子结构的理论计算证实了由于壳中 1nm GaAs 层中存在离子化碳受体，载流子在核/壳界面处的量子限制。在高磁场中的微光致发光显示出 n = 0 朗道能级发射线与 n = 2 朗道能级 TO 声子副本的避免交叉的清晰特征。这种耦合是由共振空穴-声子相互作用引起的，这表明结构中的二维空穴密度很大。
