Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kgs., Lyngby, Denmark.
Solid State Physics, Lund University, Box 118, S-221 00, Lund, Sweden.
Small. 2015 Jun 10;11(22):2687-95. doi: 10.1002/smll.201403361. Epub 2015 Feb 5.
The doping process in GaP core-shell nanowire pn-junctions using different precursors is evaluated by mapping the nanowires' electrostatic potential distribution by means of off-axis electron holography. Three precursors, triethyltin (TESn), ditertiarybutylselenide, and silane are investigated for n-type doping of nanowire shells; among them, TESn is shown to be the most efficient precursor. Off-axis electron holography reveals higher electrostatic potentials in the regions of nanowire cores grown by the vapor-liquid-solid (VLS) mechanism (axial growth) than the regions grown parasitically by the vapor-solid (VS) mechanism (radial growth), attributed to different incorporation efficiency between VLS and VS of unintentional p-type carbon doping originating from the trimethylgallium precursor. This study shows that off-axis electron holography of doped nanowires is unique in terms of the ability to map the electrostatic potential and thereby the active dopant distribution with high spatial resolution.
通过离轴电子全息术来绘制纳米线的静电势分布，评估了使用不同前体制备 GaP 核壳纳米线 pn 结的掺杂过程。研究了三种前体，三乙基锡（TESn）、二特丁基硒化物和硅烷，用于纳米线壳的 n 型掺杂；其中，TESn 被证明是最有效的前体。离轴电子全息术显示，通过汽-液-固（VLS）机制（轴向生长）生长的纳米线核心区域的静电势高于通过汽-固（VS）机制（径向生长）寄生生长的区域，这归因于不同的掺入效率 VLS 和 VS 之间的非故意 p 型碳掺杂，源自三甲基镓前体。这项研究表明，掺杂纳米线的离轴电子全息术在以高空间分辨率绘制静电势从而绘制活性掺杂剂分布的能力方面具有独特性。
