Iron impurities drive Zn-rich phase formation in CdZnTe crystals

ÜNAL M., Sedani S. S., YILDIZ İ., BALBAŞI Ö. B., TURAN R.

Materials Letters, cilt.403, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 403
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.matlet.2025.139521
  • Dergi Adı: Materials Letters
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
  • Anahtar Kelimeler: 3D ToF-SIMS analysis, CdZnTe crystals, Impurities, THM growth, Zn phase formation
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

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.