Division of Solid State Physics and NanoLund, Lund University , P.O. Box 118, SE-221 00 Lund, Sweden.
Nano Lett. 2017 Feb 8;17(2):702-707. doi: 10.1021/acs.nanolett.6b03795. Epub 2017 Jan 5.
Semiconductor nanowires are versatile building blocks for optoelectronic devices, in part because nanowires offer an increased freedom in material design due to relaxed constraints on lattice matching during the epitaxial growth. This enables the growth of ternary alloy nanowires in which the bandgap is tunable over a large energy range, desirable for optoelectronic devices. However, little is known about the effects of doping in the ternary nanowire materials, a prerequisite for applications. Here we present a study of p-doping of InGaP nanowires and show that the growth dynamics are strongly affected when diethylzinc is used as a dopant precursor. Specifically, using in situ optical reflectometry and high-resolution transmission electron microscopy we show that the doping results in a smaller nanowire diameter, a more predominant zincblende crystal structure, a more Ga-rich composition, and an increased axial growth rate. We attribute these effects to changes in seed particle wetting angle and increased TMGa pyrolysis efficiency upon introducing diethylzinc. Lastly, we demonstrate degenerate p-doping levels in InGaP nanowires by the realization of an Esaki tunnel diode. Our findings provide insights into the growth dynamics of ternary alloy nanowires during doping, thus potentially enabling the realization of such nanowires with high compositional homogeneity and controlled doping for high-performance optoelectronics devices.
半导体纳米线是光电设备的多功能构建模块,部分原因是纳米线在进行外延生长时对晶格匹配的限制放宽,从而在材料设计方面提供了更大的自由度。这使得能够生长带隙在很大能量范围内可调谐的三元合金纳米线,这对于光电设备是理想的。然而,对于掺杂在三元纳米线材料中的影响知之甚少,这是应用的前提。在这里,我们研究了 InGaP 纳米线的 p 型掺杂,并表明当使用二乙基锌作为掺杂前体时,生长动力学受到强烈影响。具体而言,我们使用原位光学反射率测量和高分辨率透射电子显微镜表明,掺杂导致纳米线直径更小、更主要的闪锌矿晶体结构、更富 Ga 的组成以及轴向生长速率增加。我们将这些效应归因于引入二乙基锌后种子颗粒润湿性角的变化和 TMGa 热解效率的提高。最后,我们通过实现 Esaki 隧道二极管证明了 InGaP 纳米线中的简并 p 型掺杂水平。我们的发现提供了对掺杂过程中三元合金纳米线生长动力学的深入了解,从而有可能实现具有高组成均匀性和受控掺杂的此类纳米线,以用于高性能光电设备。