Akademik Veri Yönetim Sistemi
Materials Science in Semiconductor Processing, cilt.211, 2026 (SCI-Expanded, Scopus)
The present study explores the impact of Ag incorporation and Ag deposition sequence in the precursor stack on the structural and optical behavior of CZTS thin films, as well as the performance enhancement of Cu2ZnSnS4 (CZTS) based thin film photodetectors (PDs) achieved through Ag doping and variations in stacking order. The fabricated Ag-doped CZTS thin films were prepared by the magnetron sputtering method using multiple layer stacking orders, as follows: ZnS/Cu/Sn/Cu (CZTS-I), ZnS/Cu/Sn/Cu/Ag (CZTS-II), ZnS/Cu/Sn/Ag/Cu (CZTS-III), ZnS/Cu/Ag/Sn/Cu (CZTS-IV), ZnS/Ag/Cu/Sn/Cu (CZTS-V), and Ag/ZnS/Cu/Sn/Cu (CZTS-VI). Raman analysis confirmed the kesterite CZTS structure while also revealing the existence of the Cu2SnS3 (CTS) secondary phase in the CZTS films, which disappeared with Ag-doping. CZTS-IV and CZTS-V exhibited enhanced grain growth, a dense structure, and a smooth surface. The band gap showed a slight upward shift from 1.44 eV (CZTS-I) to 1.54 eV (CZTS-V). The PL emission was observed at ∼1.37 eV, appearing below the optical band gap due to Donor–Acceptor Pair (DAP) recombination. Among the prepared films, the CZTS-IV sample showed the highest PL intensity, indicating a significant reduction in non-radiative recombination centers. Urbach energy (EU) of the CZTS and Ag-doped CZTS samples revealed that EU value decreased as the position of Ag in the precursor layer changed from the top to the bottom, reaching an optimal level in CZTS-IV (279 meV). Current-voltage (I-V) measurements indicated a linear relationship between current and voltage under both dark and illuminated conditions, confirming the ohmic nature of all devices. The fastest rise and fall times (11 ms each) were achieved by the CZTS-IV thin-film PD under blue light at 2 V, attributed to its superior structural and optical properties. CZTS-II demonstrated the highest responsivity (R = 2.40 mA/W), detectivity (D∗ = 3.4 × 108 Jones), and external quantum efficiency (EQE = 0.662) under blue light. These improvements are credited to both Ag-doping and the optimized stacking order. It was seen that the Ag layer precursor stacking sequence plays a crucial role in the structural evolution of CZTS films by regulating elemental interdiffusion, intermediate phase formation, and grain growth during sulfurization. This study highlights the potential of Ag-doped CZTS thin-film PDs for future high-performance devices.