Iron impurities drive Zn-rich phase formation in CdZnTe crystals
Materials Letters, vol.403, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 403
- Publication Date: 2026
- Doi Number: 10.1016/j.matlet.2025.139521
- Journal Name: Materials Letters
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
- Keywords: 3D ToF-SIMS analysis, CdZnTe crystals, Impurities, THM growth, Zn phase formation
- Middle East Technical University Affiliated: Yes
Abstract
The yield of detector-grade CdZnTe (CZT) crystals remains limited by impurity segregation during traveling heater method (THM) growth. Here we investigate the role of unintentional Fe impurities in driving Zn-rich phase formation near the last-to-freeze region of CZT ingots. Infrared microscopy revealed the progressive evolution of opaque domains into needle-like structures. XPS analysis identified Zn enrichment on those opaque domains, and three-dimensional ToF-SIMS mapping demonstrated Fe accumulation within these domains. The co-localization of Fe and Zn phases suggests that Fe impurities facilitate heterogeneous nucleation and growth of Zn-rich inclusions. Such impurity-decorated phases act as recombination centers, compromising carrier transport and detector performance. These findings provide the first direct evidence linking Fe segregation to Zn-phase formation and highlight the importance of feedstock purification and growth optimization for improving CZT detector yield.