Structural Insights on Microwave-Synthesized Antimony-Doped Germanium Nanocrystals
Structural Insights on Microwave-Synthesized Antimony-Doped Germanium Nanocrystals
复制标题
微波合成锑掺杂锗纳米晶体的结构见解
DOI：
10.1021/acsnano.0c09352
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发表时间：
2021
期刊：
影响因子：
17.1
通讯作者：
Carter, Sue A.
中科院分区：
文献类型：
--
作者：
Tabatabaei, Katayoon;Sully, Heather R.;Ju, Zheng;Hellier, Kaitlin;Lu, Haipeng;Perez, Christopher J.;Newton, Kathryn A.;Brutchey, Richard L.;Bridges, Frank;Carter, Sue A.
掺杂和合金化的锗纳米晶体（Ge NCs）是用于光电子学和近红外探测器等各种应用的潜在候选者。最近，铋（Bi）作为ann型第15族元素被证明是成功的，并通过微波辅助的基于溶液的合成动力学掺杂到Ge NC中，虽然Bi是化学上不溶于块体结晶Ge。为了扩展Ge NCs的成分操纵，研究了半导体中另一种更常见的n型15族元素锑（Sb）。利用微波辅助下GeI 2和SbI 3的溶液反应合成了油胺（OAm）和油胺/三辛基膦（TOP）修饰的Sb掺杂Ge纳米晶。与单独的OAM相比，用OAM/TOP的二元配体系统钝化Ge表面导致形成一致的更大的NC。通过~（31）P NMR和SEM-EDS分析证实了TOP在Ge表面的配位。Ge纳米碳的晶格常数随着Sb浓度的增加（0.00-2.0 mol %）而增加，这与Sb的掺入一致。TEM显示，在反应中，随着SbI 3含量的增加，纳米碳的直径增加。XPS和EDS证实了Sb的存在之前和之后的表面配位体与肼和recapping的Ge NC表面与十二烷乙烷（DDT）的去除。EXAFS分析表明，Sb驻留在NC的高度扭曲的网站旁边的Ge空缺，以及在微晶表面上。高Urbach能量从光热偏转光谱（PDS）的原始Ge NC和Sb掺杂的Ge NC制备的薄膜表明高水平的无序，与EXAFS数据一致。二氧化钛-NC电子和空穴的设备上的电气测量显示空穴传导的增加，这表明Sb空位缺陷的行为作为AP型掺杂剂的Ge NC，一致的空位模型来自EXAFS结果。
Doped and alloyed germanium nanocrystals (Ge NCs) are potential candidates for a variety of applications such as photovoltaics and near IR detectors. Recently, bismuth (Bi) as ann-type group 15 element was shown to be successfully and kinetically doped into Ge NCs through a microwave-assisted solution-based synthesis, although Bi is thermodynamically insoluble in bulk crystalline Ge. To expand the composition manipulation of Ge NCs, another more commonn-type group 15 element for semiconductors, antimony (Sb), is investigated. Oleylamine (OAm)- and OAm/trioctylphosphine (TOP)-capped Sb-doped Ge NCs have been synthesized by the microwave-assisted solution reaction of GeI2with SbI3. Passivating the Ge surface with a binary ligand system of OAm/TOP results in formation of consistently larger NCs compared to OAm alone. The TOP coordination on the Ge surface is confirmed by31P NMR and SEM-EDS. The lattice parameter of Ge NCs increases with increasing Sb concentration (0.00–2.0 mol %), consistent with incorporation of Sb. An increase in the NC diameter with higher content of SbI3in the reaction is shown by TEM. XPS and EDS confirm the presence of Sb before and after removal of surface ligands with hydrazine and recapping the Ge NC surface with dodecanethiol (DDT). EXAFS analysis suggests that Sb resides within the NCs on highly distorted sites next to a Ge vacancy as well as on the crystallite surface. High Urbach energies obtained from photothermal deflection spectroscopy (PDS) of the films prepared from pristine Ge NC and Sb-doped Ge NCs indicate high levels of disorder, in agreement with EXAFS data. Electrical measurements on TiO2–NC electron- and hole-only devices show an increase in hole conduction, suggesting that the Sb-vacancy defects are behaving as ap-type dopant in the Ge NCs, consistent with the vacancy model derived from the EXAFS results.