Trap-assisted reverse bias NDR and high-performance photodetection in Ti-doped amorphous WO3 heterojunctions
OPTICAL MATERIALS, cilt.179, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 179
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.optmat.2026.118292
- Dergi Adı: OPTICAL MATERIALS
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Hatay Mustafa Kemal Üniversitesi Adresli: Evet
Özet
This study investigates the electrical and optoelectronic properties of undoped and Ti-doped amorphous WO3 thin films grown by the DC magnetron sputtering method and layered into ITO/WO3/Ag, ITO/W1-xTixO3/Ag, and ITO/W1-yTiyO3/Ag structures. Current-voltage (I-V) measurements were conducted in the dark and under 100 mW/cm2, with over a +/- 3 V range at room temperature. The basic electrical parameters, such as the reverse saturation current (I0), ideality factor (n), zero-bias barrier height (Phi B0), and series resistance (Rs), were calculated from several methods. Tauc analysis showed that optimal Ti doping (S2) narrowed the optical band gap from 3.10 eV to 3.07 eV by creating shallow traps within the oxide network. In the dark I-V, both S1 and S2 structures exhibited notable negative differential resistance in the reverse-bias region, which was attributed to a trap-assisted tunneling mechanism. At under 100 mW/cm2, the photon-induced trap-filling effect resulted in a massive decrease in the Rs. Optoelectronic parameters revealed that the S2 structure exhibited notable performance, achieving a photo-sensitivity (S) of 7160. With this, the responsivity (R) and specific detectivity (D*) of the structure were found to be 2.00 A/W and 5.88 & times; 1011 Jones, respectively. In contrast, high Ti doping decimated the photonic performance of the device by structurally forming deep recombination centers in the S3 (S congruent to 6.5). Furthermore, transient photoresponse measurements revealed a bias-dependent multi-state behavior, transitioning from positive photocurrent (PPC) at zero bias to an anomalous negative photocurrent (NPC) dip at moderate reverse biases, and ultimately evolving into a resistive switching state at high electric fields.