Robles Rosemary Cortes, Torres Vincent G Marrero, Trinh Cong Tai, Pettes Michael T, James Ralph B, Egarievwe Stephen U, Drabo Mebougna, Roy Utpal N, Palai Ratnakar, Htoon Han, Jones Andrew C
Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Department of Physics, University of Puerto Rico, Rio Piedras, San Juan, PR, 00931, USA.
Sci Rep. 2025 Aug 30;15(1):31996. doi: 10.1038/s41598-025-15132-3.
While CdZnTe (CZT) and CdZnTeSe (CZTS) semiconductors have emerged as compounds for room-temperature gamma and X-ray detection materials, they continue to be constrained by the formation of Te-inclusion defects generated during the growth and post-growth phases of the material, which adversely affect the detector performance. We demonstrate the utility of multimodal microscopic imaging and analysis for the characterization of the optical and electronic properties of Te inclusions in CZT and CZTS crystals at both micron and nanometer length scales. Having first identified regions with micron-scale Te inclusions using confocal Raman microscopy techniques, optically coupled infrared scattering near-field optical microscopic mapping was performed to map the distribution of these inclusions with nanometer spatial resolution and correlate the presence of Te inclusions in the matrix with other properties. Kelvin probe force microscopy was then utilized to characterize the variations of the work function associated with the presence of Te inclusions. Here, we observe an increase of ~ 240 mV in the work function associated with Te inclusions compared to the bulk CZT/CZTS crystals. Additionally, we observe that individual bulk grains in CZT can exhibit slight potential variations. Our findings develop a portrait of the charge trapping mechanisms in CZT and CZTS that act to degrade detector performance, while the demonstration of these combined microscopy techniques provides a new analytical tool that can be utilized for further optimization of the detector performance for these semiconducting compounds.
虽然碲锌镉(CdZnTe,CZT)和碲锌镉硒(CdZnTeSe,CZTS)半导体已成为室温伽马射线和X射线探测材料的化合物,但它们仍然受到材料生长和生长后阶段产生的碲夹杂缺陷形成的限制,这对探测器性能产生了不利影响。我们展示了多模态显微成像和分析在表征CZT和CZTS晶体中碲夹杂的光学和电子特性方面的效用,该表征在微米和纳米长度尺度上均适用。首先使用共焦拉曼显微镜技术识别出含有微米级碲夹杂的区域,然后进行光耦合红外散射近场光学显微镜测绘,以纳米空间分辨率绘制这些夹杂的分布,并将基质中碲夹杂的存在与其他特性相关联。接着利用开尔文探针力显微镜来表征与碲夹杂存在相关的功函数变化。在此,我们观察到与碲夹杂相关的功函数相比块状CZT/CZTS晶体增加了约240 mV。此外,我们观察到CZT中的单个块状晶粒可能会表现出轻微的电位变化。我们的研究结果描绘了CZT和CZTS中导致探测器性能下降的电荷俘获机制,而这些组合显微镜技术的展示提供了一种新的分析工具,可用于进一步优化这些半导体化合物的探测器性能。