NUMERICAL INVESTIGATION OF CNGS KESTERITE-BASED DUAL-FUNCTIONAL OPTOELECTRONIC DEVICES FOR PHOTOVOLTAIC AND PHOTODETECTION APPLICATIONS
III. Uluslararası Kapadokya Akademik Çalışmalar Kongresi, Nevşehir, Türkiye, 6 - 08 Ekim 2026, cilt.1, sa.1, ss.1-16, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Cilt numarası: 1
- Basıldığı Şehir: Nevşehir
- Basıldığı Ülke: Türkiye
- Sayfa Sayıları: ss.1-16
- Yozgat Bozok Üniversitesi Adresli: Evet
Özet
ABSTRACT
This study presents a systematic SCAPS-1D-based numerical investigation of Cu₂NiGeS₄ (CNGS) kesterite as a dual-functional optoelectronic platform in which photovoltaic and photodetection functionalities are jointly assessed within the same device architecture. CNGS is a promising absorber for thin-film optoelectronics due to its direct bandgap of 1.78 eV, an optical absorption coefficient on the order of 10⁴ cm⁻¹, and constituent elements with relatively low toxicity. Despite these advantages, an integrated evaluation of the photodetector mode together with capacitance spectroscopy (C–V, C–f) for CNGS-based devices remains limited in the literature. To address this gap, two candidate architectures are proposed: FTO/In_2 S_3/CNGS/Au and FTO/In_2 S_3/CNGS/CuGaSe₂(CGS)/Au. In the solar-cell mode under standard AM1.5G illumination, key performance parameters including open-circuit voltage (V_oc), short-circuit current density (J_sc), fill factor (FF), and power conversion efficiency (PCE) are calculated. In the photodetector mode under reverse bias, the dark current density (J_dark), responsivity (R), and specific detectivity (D^*) are extracted. The performed capacitance spectroscopy enables a comprehensive characterization of the physical processes governing junction dynamics and carrier transport mechanisms. Overall, this work numerically demonstrates the scientific feasibility of CNGS for dual-functional optoelectronic applications and provides a solid theoretical basis, supported by concrete device parameters, to guide future experimental studies.
Keywords: Cu₂NiGeS₄ (CNGS); SCAPS-1D; dual-functional device; photodetector; capacitance spectroscopy