New thermally stimulated emission spectrometer for the detection of ultra-shallow low-density traps
New thermally stimulated emission spectrometer for the detection of ultra-shallow low-density traps
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DOI：
10.1063/5.0050938
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发表时间：
2021-07
影响因子：
3.2
通讯作者：
M. Islam;M. Bakr;J. N. Aboa;F. Selim
中科院分区：
文献类型：
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作者：
M. Islam;M. Bakr;J. N. Aboa;F. Selim
电子/空穴陷阱通过创造额外的重组途径、捕获或提供电荷载流子以及改变激子动力学来改变材料的光学和电学性质。了解缺陷/陷阱动力学对于控制材料的光电特性至关重要，而测量供体/受体电离能在半导体研究中至关重要。在这里，我们开发了一个高灵敏度的热激发发射（TSE）光谱仪，用于9-325 K的低温区，以提高灵敏度检测和表征带隙材料中的浅阱。它为广泛的半导体、电子和光子材料提供了强大的表征工具。在粉末、不规则形状和厚度以及高电阻样品等不能使用电方法进行供体/受体表征的情况下，该技术是理想的。在掺Ce的Y3Al5O12单晶上测试了光谱仪的性能，测量结果发现了几个传统方法无法检测到的浅能级。然后，通过检测Ga2O3中的浅层水平进一步证明了其能力，Ga2O3正在成为高功率器件和光电子器件的特殊半导体。采用一种基于三点分析（TPA）方法的复杂数据分析技术对高度重叠的TSE信号进行反卷积。所开发的超低温光谱仪与TPA反褶积方法为研究光子材料中的激子动力学和测量发光半导体中的供体/受体电离能和密度提供了独特的工具。它将促进广泛应用的材料表征和开发，包括激光、电子和照明设备以及用于医疗诊断和核应用的探测器。
Electron/hole traps alter the optical and electrical properties of materials by creating additional recombination pathways, trapping or providing charge carriers and modifying exciton dynamics. Understanding the defect/trap dynamics is crucial to control the optoelectronic properties of materials, and measuring donor/acceptor ionization energy is critical in semiconductor research. Here, we developed a highly sensitive thermally stimulated emission (TSE) spectrometer for the low temperature regime of 9–325 K to detect and characterize shallow traps in bandgap materials with enhanced sensitivity. It provides a powerful characterization tool for a wide range of semiconductors and electronic and photonic materials. This technique is ideal where electrical methods cannot be used for donor/acceptor characterization as in powder, irregular shape and thickness, and high resistive samples. The performance of the spectrometer was tested on Ce doped Y3Al5O12 single crystals, and the measurements identified several shallow levels that cannot be detected with conventional methods. Then, its capabilities were further demonstrated by detecting a shallow level in Ga2O3, which is emerging as an exceptional semiconductor for high-power devices and optoelectronics. A sophisticated data analysis technique based on the three-point analysis (TPA) approach was applied to deconvolute the highly overlapped TSE signals. The developed ultra-low temperature spectrometer together with the TPA deconvolution method provides a unique tool for studying exciton dynamics in photonic materials and measuring donor/acceptor ionization energies and densities in luminescent semiconductors. It will advance material characterization and development for a wide range of applications including lasers, electronic and illumination devices, and detectors for medical diagnostic and nuclear applications.