Enhanced IR transmittance of CZT substrates: Surface processing and Cd-saturated annealing

IF 2.5 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth Pub Date : 2026-01-01 Epub Date: 2025-11-01 DOI:10.1016/j.jcrysgro.2025.128395

Shangshu Li , Xiaolu Xiong , Chao Xu , Changhe Zhou

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引用次数: 0

Abstract

The IR transmission behavior of Cd_1-_xZn_xTe (CZT) slices can provide useful information about inclusion/precipitate feature, stoichiometry and free carriers. High infrared (IR) transmittance is essential for the application of CZT in infrared focal plane arrays (IRFPA). The IR transmittance features of the CZT slices with different surface states are analyzed, and the indicator T₆₂₅ is used to assess whether the slices should be annealed or not. The preprocessed CZT slices with rough surfaces and T₆₂₅ < 45 % are annealed under Cd-saturated atmosphere, and results demonstrate that IR transmittance improvement is insignificant either by increasing annealing time or temperature. Furthermore, the (111) Cd and (111) Te surfaces are respectively ground (to obtain smooth surfaces) and annealed. The result shows the IR transmittance improvement of slices ground on (111) Cd surface is more obvious compared with slices ground on (111) Te surface. Density functional theory (DFT) calculations were also employed to investigate the reaction mechanism between molecular oxygen and CdTe, and the theoretical calculation results indicate that (111) Te surface is more easily oxidized than (111) Cd surface. The experimental and theoretical results demonstrate the presence of oxidation layer can account for the ineffective IR transmittance improvement. Additionally, a cost-effective CZT substrate processing is proposed in this study.

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提高CZT衬底的红外透射率：表面处理和饱和镉退火

Cd1-xZnxTe （CZT）薄片的红外透射行为可以提供有关包裹/沉淀特征、化学计量学和自由载流子的有用信息。高红外透过率是CZT在红外焦平面阵列（IRFPA）中应用的必要条件。分析了不同表面状态CZT薄片的红外透射率特征，并利用T625指标评价了薄片是否需要退火。对表面粗糙、T625 <； 45%的经预处理的CZT薄片在饱和镉气氛下进行退火，结果表明，增加退火时间和温度对其红外透射率的提高都不显著。此外，（111）Cd和（111）Te表面分别进行研磨（以获得光滑表面）和退火。结果表明，（111）Cd表面的薄片比（111）Te表面的薄片红外透过率提高更明显。采用密度泛函理论（DFT）研究了分子氧与CdTe的反应机理，理论计算结果表明（111）Te表面比（111）Cd表面更容易被氧化。实验和理论结果表明，氧化层的存在是导致红外透过率提高效果不明显的原因。此外，本研究还提出了一种具有成本效益的CZT衬底加工方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Crystal Growth 化学-晶体学

CiteScore

3.60

自引率

11.10%

发文量

373

审稿时长

65 days

期刊介绍： The journal offers a common reference and publication source for workers engaged in research on the experimental and theoretical aspects of crystal growth and its applications, e.g. in devices. Experimental and theoretical contributions are published in the following fields: theory of nucleation and growth, molecular kinetics and transport phenomena, crystallization in viscous media such as polymers and glasses; crystal growth of metals, minerals, semiconductors, superconductors, magnetics, inorganic, organic and biological substances in bulk or as thin films; molecular beam epitaxy, chemical vapor deposition, growth of III-V and II-VI and other semiconductors; characterization of single crystals by physical and chemical methods; apparatus, instrumentation and techniques for crystal growth, and purification methods; multilayer heterostructures and their characterisation with an emphasis on crystal growth and epitaxial aspects of electronic materials. A special feature of the journal is the periodic inclusion of proceedings of symposia and conferences on relevant aspects of crystal growth.