Low-Level UV Detection Using Channel-Width Optimized TiO2Phototransistor
ACS Applied Electronic Materials, cilt.7, sa.18, ss.8561-8570, 2025 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 7 Sayı: 18
- Basım Tarihi: 2025
- Doi Numarası: 10.1021/acsaelm.5c01360
- Dergi Adı: ACS Applied Electronic Materials
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex
- Sayfa Sayıları: ss.8561-8570
- Anahtar Kelimeler: carrier mobility, channel engineering, detectivity, MOSFETs, photoresponsivity, subthreshold swing, titanium dioxide (TiO2), transconductance, UV phototransistors
- Gazi Üniversitesi Adresli: Evet
Özet
We report on the fabrication and UV photoresponse characteristics of TiO2-based phototransistors (TiO2–PTs) incorporating a TiO2/SiN active layer grown on Si substrates via electron beam evaporation. Devices with fixed channel length (∼2.5 μm) and varying channel widths (6.0, 7.5, and 9.0 μm) were fabricated to examine geometric effects on optoelectronic behavior. All PTs exhibit well-defined I–V characteristics and strong UV sensitivity under 18 μW, 385 nm illumination. The widest channel device (9.0 μm) demonstrated a peak responsivity of 10.5 A/W and a detectivity of 6.6 × 1010Jones at VGS= 5 V, outperforming narrower geometries in terms of carrier collection and photocurrent generation. Narrower channels demonstrate sharper switching (SS ∼ 10 V/dec) but reduced photocurrent gain due to limited absorption volume. These results highlight the crucial role of channel-width engineering in modulating responsivity, switching efficiency, and signal-to-noise characteristics. This study provides a scalable pathway for optimizing TiO2-based FET photodetectors for high-sensitivity UV imaging and environmental sensing applications.