The effect of Al2O3 surface passivation layer prepared by ALD method on the performance of CdZnTe thick film detectors

• Published in: Applied surface science 2025-02, Vol.681, p.161504, Article 161504
• Main Authors: Lin, Longhui, Huang, Haofei, Xu, Ke, Wang, Qunfang, Tang, Ke, Cao, Meng, Huang, Jian, Wang, Linjun
• Format: Article
• Language: English
• Subjects: Al2O3; ALD; CdZnTe; Surface passivation
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.161504

[Display omitted] •Al2O3 deposited by ALD effectively passivates the surface of CdZnTe thick films.•Analyzed the surface passivation mechanism of Al2O3 on CdZnTe thick films.•Investigated the optimal Al2O3 thickness for surface passivation on CdZnTe thick films.•Achieved CdZnTe thick film γ-ray detectors with energy resolution of 15.1%. In this work, cadmium zinc telluride (CdZnTe) thick films were grown using close-spaced sublimation (CSS), while Al2O3 films of varying thicknesses were deposited by atomic layer deposition (ALD) as surface passivation layers. The influence of the Al2O3 surface passivation layer on the structure, surface morphology, chemical composition and electrical performance of the CdZnTe thick films was analyzed using XRD, EDS, SEM, AFM, XPS and current–voltage (I-V) characterization systems. The results demonstrate that the surface passivation layer could significantly improves surface defects and reduces the surface leakage current (SLC) of CdZnTe thick films. The CdZnTe thick film radiation detector exhibited an improved energy resolution, decreasing from 18.6 % to 15.1 % with a 40 nm Al2O3, as measured using a 60 KeV 241Am γ-ray source.