Optical Properties of GaAs/AlGaAs Nanowires Grown on Pre-etched Si Substrates

预刻蚀硅衬底上生长的GaAs/AlGaAs纳米线的光学特性

GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.

GaAs基纳米材料由于其出色的光电性能,对于近红外纳米光电子器件至关重要。然而,随着GaAs材料尺寸的缩小,由闪锌矿(ZB)和纤锌矿(WZ)相混合引起的Ⅱ-型量子阱结构和大的表面积体积比引起的表面缺陷严重阻碍了GaAs纳米线的发展。实现具有高发光效率的GaAs基纳米线已成为研究重点。本研究通过预刻蚀的硅衬底与形成GaAs/AlGaAs核壳异质结构相结合,利用阴影效应和表面钝化作用,制备了具有良好垂直性、优异晶体结构和高发光效率的GaAs基纳米线。这一结论的主要证据包括制备的GaAs基纳米线在变温光谱中突出的自由激子发射和变功率光谱中暗示的低热活化能。结果表明,所描述的生长方法可用于改善其他Ⅲ-Ⅴ低维材料的晶体结构和光学性能,有望为未来的纳米线器件奠定基础。