Self-Powered Broadband High-Responsivity Photodetectors: p-(CuS)<i>x</i>(ZnSe)<i>1-x</i>/p-Si Isotype Heterojunction
SMALL, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1002/smll.75048
- Dergi Adı: SMALL
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aerospace Database, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC, MEDLINE, Biomedical Reference Collection: Corporate Edition (EBSCO), Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Bursa Uludağ Üniversitesi Adresli: Evet
Özet
The increasing demand for cost-effective, high-performance, and broadband photodetectors motivates the development of novel material systems and device architectures. In this study, compositionally tunable p-(CuS)x(ZnSe)1-x/p-Si isotype heterojunction photodetectors were fabricated via thermal evaporation. The CuS/ZnSe ratio was systematically varied to investigate its impact on the morphological, optical, and electrical properties of the heterojunction. At the optimized x = 0.5 composition, densely and homogeneously distributed nanopillars enhanced light trapping and photon harvesting. Consequently, the device achieved a responsivity of 1.1 A/W, a detectivity of 1.16 & times; 1011 Jones, and an external quantum efficiency (EQE) of 161% at 850 nm under zero bias. The remarkably high EQE originates from the combined effect of enhanced light harvesting and a trap-assisted internal photoconductive gain mechanism. The valence-band offset at the heterojunction interface acts as a hole-blocking barrier, while copper vacancies identified by XPS serve as hole-trapping centers that prolong carrier lifetime and trigger electron recirculation. This mechanism was further supported by the asymmetric transient response with rise and fall times of 21 and 54 & micro;s, respectively. Ultimately, this convergence of maximized photon absorption and prolonged carrier lifetimes provides a viable strategy for designing high-gain and chalcogenide-based photodetectors for high sensing of light with very low intensity.