Evaporation-induced hexagonal-to-monoclinic phase engineering in GaSexTe1-x for self-powered broadband photodetection
JOURNAL OF ALLOYS AND COMPOUNDS, cilt.1003, sa.191767, ss.1-16, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 1003 Sayı: 191767
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.jallcom.2026.191767
- Dergi Adı: JOURNAL OF ALLOYS AND COMPOUNDS
- Derginin Tarandığı İndeksler: Academic Search Ultimate (EBSCO), Engineering Source (EBSCO), Scopus, Science Citation Index Expanded (SCI-EXPANDED), Chemical Abstracts Core, Chimica, Compendex, INSPEC, Public Affairs Index
- Sayfa Sayıları: ss.1-16
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
The fundamental control of structural phase transitions in ternary layered chalcogenide alloys is paramount for tailoring thermodynamic stability and electronic properties. Here, we report a composition-driven hexagonal-to- monoclinic phase-engineering approach achieved via the thermal evaporation of Bridgman-grown GaSe0.6Te0.4 bulk crystals onto p-type GaAs substrates. Advanced structural mapping, combining complementary experimental and simulated X-ray diffraction with resonant Raman spectroscopy and density functional theory (DFT) calculations, reveals that partial Se depletion during vacuum thermal processing shifts the local Te/Se stoichiometry, thereby energetically stabilizing the monoclinic (C2/m) phase over the initial hexagonal matrix. Atomic force microscopy identifies a highly dense, uniform thin-film morphology governed by the Volmer-Weber island growth mode, indicating efficient lattice strain relaxation at the heterointerface. Crucially, this non-equilibrium phase transformation dramatically alters the interface energetics, optimizing the junction's built-in potential and charge-separation dynamics. Operating under zero-bias conditions, the resulting vertically integrated Ag/In/ GaSeTe/p-GaAs/Cu/Ag heterojunction device exhibits exceptional self-powered optoelectronic properties: an ultra-low dark current of 3.40 ×10 11 A, a peak specific detectivity of 2.37 ×1011 Jones, and a noise equivalent power of 8.37 ×10 13 W/Hz1/2 at 820 nm, alongside rapid microsecond transit times (110/160 μs). This study provides an explicit processing-structure-property framework for utilizing thermal processing to engineer phase boundaries in ternary 2D alloys for advanced functional architectures.