A comparative study of epitaxial InGaAsBi/InP structures using Rutherford backscattering spectrometry, X-ray diffraction and photoluminescence techniques
A comparative study of epitaxial InGaAsBi/InP structures using Rutherford backscattering spectrometry, X-ray diffraction and photoluminescence techniques
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DOI：
10.1063/1.5109653
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发表时间：
2019-09
影响因子：
3.2
通讯作者：
M. Sharpe;I. Marko;D. A. Duffy;J. England;E. Schneider;M. Kesaria;V. Fedorov;E. Clarke;C. Tan;S. Sweeney
中科院分区：
文献类型：
--
作者：
M. Sharpe;I. Marko;D. A. Duffy;J. England;E. Schneider;M. Kesaria;V. Fedorov;E. Clarke;C. Tan;S. Sweeney
在这项工作中，我们使用光致发光（PL），高分辨率x射线衍射（XRD）和卢瑟福后向散射光谱（RBS）技术的组合来研究mbe生长的InGaAsBi样品（有和没有InGaAs帽层）的材料质量和结构性能，目标铋成分在3%-4%范围内。XRD数据表明，未封盖样品的InGaAsBi层更加均匀。对于封顶样品，InGaAs封顶层在较高温度下的生长影响了InGaAsBi层的质量和生长方向上的铋分布。低温PL呈现多个发射峰；利用峰能、峰宽、峰强度与XRD、RBS结果进行对比分析。随机方向的RBS数据与通道测量一起可以估计铋成分和分析结构性质。由于在较高温度下生长的封顶样品中可能存在反位缺陷，RBS通道显示出较高应变的证据。研究还表明，盖帽层在高温下的生长导致铋层质量的恶化。RBS分析表明，随着铋浓度的增加，未封顶InGaAsBi层的均匀性降低。未封顶的高铋浓度样品显示较少的沟道倾角，表明样品表面的铋晶体质量较差和聚集。
In this work, we used a combination of photoluminescence (PL), high resolution X-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) techniques to investigate material quality and structural properties of MBE-grown InGaAsBi samples (with and without an InGaAs cap layer) with targeted bismuth composition in the 3%–4% range. XRD data showed that the InGaAsBi layers are more homogeneous in the uncapped samples. For the capped samples, the growth of the InGaAs capped layer at higher temperature affects the quality of the InGaAsBi layer and bismuth distribution in the growth direction. Low-temperature PL exhibited multiple emission peaks; the peak energies, widths, and relative intensities were used for comparative analysis of the data in line with the XRD and RBS results. RBS data at a random orientation together with channeled measurements allowed both an estimation of the bismuth composition and analysis of the structural properties. The RBS channeling showed evidence of higher strain due to possible antisite defects in the capped samples grown at a higher temperature. It is also suggested that the growth of the capped layer at high temperature causes deterioration of the bismuth-layer quality. The RBS analysis demonstrated evidence of a reduction of homogeneity of uncapped InGaAsBi layers with increasing bismuth concentration. The uncapped higher bismuth concentration sample showed less defined channeling dips suggesting poorer crystal quality and clustering of bismuth on the sample surface.