Forming-free Al/ZnO/Al memristors as near-ideal physical unclonable functions: Surface defect chemistry and interfacial conduction analysis
Materials Science in Semiconductor Processing, cilt.216, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 216
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.mssp.2026.111070
- Dergi Adı: Materials Science in Semiconductor Processing
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Chemical Abstracts Core, Chimica, Compendex, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Anahtar Kelimeler: Al/znO interface, Grain-boundary oxygen vacancies, Physical unclonable function, Poole-Frenkel emission, Resistive switching memristor, ZnO thin films
- Recep Tayyip Erdoğan Üniversitesi Adresli: Evet
Özet
We report the fabrication, surface characterisation, conduction-mechanism analysis, and physical unclonable function (PUF) evaluation of Al/ZnO/Al memristors prepared by DC reactive magnetron sputtering on SiO2/p++Si. X-ray diffraction confirms the hexagonal wurtzite ZnO phase; the broad diffraction envelope of the as-deposited film (D ≲ 5 nm) indicates a nanocrystalline microstructure rich in grain-boundary oxygen vacancies. Atomic force microscopy reveals a columnar-pyramidal surface texture (Ra = 44 nm) consistent with c-axis-aligned grain growth. The Tauc-plot optical bandgap is 3.2 eV, and room-temperature photoluminescence shows a dominant deep-level emission at 600 nm (2.07 eV) and a near-band-edge emission at 389 nm (3.19 eV) with a peak-intensity ratio DLE/NBE ≈ 6, confirming the high oxygen-vacancy concentration that drives forming-free switching. The devices exhibit bipolar resistive switching with VSET = 0.63 V, VRESET = −0.50 V and an HRS/LRS current ratio exceeding 80×. Conduction analysis identifies Ohmic transport (slope ≈ 1.0) in the LRS and Poole–Frenkel emission (slope ≈ 5.4) in the HRS, consistent with oxygen-vacancy filamentary switching. An 82-device PUF test set achieves uniformity = 0.500 and inter-device uniqueness = 0.506 — both within 1.2% of the theoretical ideal — without any electroforming step. The deliberate harvesting of process-induced current variability (coefficient of variation = 115%) offers a new design paradigm for resource-constrained IoT security primitives.