Pitch-Induced Bandgap Tuning in Self-Catalyzed Growth of Patterned GaAsSb Axial and GaAs/GaAsSb Core?Shell Nanowires Using Molecular Beam Epitaxy
Pitch-Induced Bandgap Tuning in Self-Catalyzed Growth of Patterned GaAsSb Axial and GaAs/GaAsSb Core?Shell Nanowires Using Molecular Beam Epitaxy
复制标题
利用分子束外延自催化生长图案化 GaAsSb 纳米线和 GaAs/GaAsSb 核壳纳米线中的节距诱导带隙调节
DOI：
10.1021/acs.cgd.6b01577
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发表时间：
2016
影响因子：
3.8
通讯作者：
Iyer, Shanthi
中科院分区：
文献类型：
--
作者：
Sharma, Manish;Karim, Md Rezaul;Kasanaboina, Pavan;Li, Jia;Iyer, Shanthi
报道了Ga辅助分子束外延生长的GaAsSb（轴向）和GaAs/GaAsSb（核-壳）垂直纳米线（NW）阵列的间距诱导带隙调谐。在轴向和核壳结构中，观察到间距为200 ~ 1200 nm的NW阵列的4K微光致发光（μ-PL）谱峰在40-50 meV范围内发生红移。PL峰强度的变化密切遵循使用有限维时域模拟计算的NW阵列的节距长度上的光吸收依赖性。一个半经验的质量守恒的生长物种为基础的模型已被提出涵盖不同的物质途径。二次通量重新发射的侧刻面的相邻的纳米线的贡献基本上朝着生长较小的间距长度，而那些从氧化物表面占主导地位的较大间距长度高V/III束等效压力比。实验和模拟结果之间的良好协议已被观察到的间距依赖的轴向和径向NW尺寸的轴向和核壳配置的GaAsSb纳米线。这项研究表明，通过简单地改变NW阵列节距长度，图案化NW的带隙调谐的适用性有很大的希望。
We report on the pitch-induced bandgap tuning in GaAsSb (axial) and GaAs/GaAsSb (core–shell) patterned vertical nanowire (NW) arrays grown by Ga-assisted molecular beam epitaxy on Si(111). Red shifts in the range of 40–50 meV in the 4 K micro-photoluminescence (μ-PL) spectral peaks have been observed, for NW arrays with pitch length variation from 200 to 1200 nm, in the axial and core–shell configurations. The variation in the PL peak intensity closely follows the optical absorption dependency on the pitch length of the NW array computed using finite dimension time domain simulation. A semiempirical mass conservation of the growth-species-based-model has been proposed encompassing different material pathways. The secondary fluxes re-emitted from the side facets of the neighboring NWs contribute substantially toward the growth for smaller pitch lengths, while those from the oxide surface dominate at larger pitch lengths for high V/III beam equivalent pressure ratios. Excellent agreement between the experimental and simulated results have been observed for the pitch dependent axial and radial NW dimensions of both the axial and core–shell configured GaAsSb NWs. This study shows great promise for the applicability of patterned NWs for band gap tuning by simply varying the NW array pitch length.