AbstractResistive Random Access Memory (ReRAM) is an emerging class of non-volatile memory that stores data by altering the resistance of a material within a memory cell. Unlike traditional memory technologies, ReRAM operates by using voltage to induce a resistance change in a metal oxide layer, which can then be read as a binary state (0 or 1). In this work, we present a flexible, forming-free, ReRAM device using an aluminium-doped zinc oxide (AZO) electrode and a nickel oxide (NiO) active layer. The fabricated Ti/NiO/AZO/PET device demonstrates reliable bipolar resistive switching (BRS) with two distinct and stable resistance states, crucial for neuromorphic computing. Electrical tests showed stable high and low resistance states with set voltage (VSET) ≈ 5.4 V and reset voltage (VRESET) ≈ 2.9 V, with endurance over 400 cycles and retention around 10³ seconds. Different conduction mechanisms were observed in high resistance state (HRS) and low resistance state (LRS) like ohmic and space charge limited current (SCLC). Electrical characterization under bending conditions demonstrated the device’s performance and reliability, with minimal variation in VSET and VRESET values. These results highlight the potential of NiO/AZO-based flexible ReRAM for high-density data storage and wearable electronics applications.
IntroductionThe need to surpass the von Neumann limit has never been more crucial than the present times when data consumption and computation have increased exponentially because of artificial intelligence. Although the advancement in traditional computer hardware has been rapid, the movement of data in a physically separate memory and processing unit introduces latency which can impact the overall performance and speed of the system1,2. Researchers have focused on going beyond von Neumann architecture, inspired by the human brain exhibiting in-memory computing, resulting in neuromorphic systems3. This neuromorphic system, coupled with the flexibility to conform to various shapes and surfaces, when combined with the existing Internet of Things may provide flexible neuromorphic electronics that are uniquely suited for a wide array of applications; from wearable health monitors to smart textiles, from adaptive industrial sensors and next-generation prosthetics to advanced data encryption4,5,6,7.The energy efficiency demand and real-time data processing requirement of these flexible neuromorphic electronic systems can be met by emerging non-volatile memory technologies such as ReRAM, phase change memory, magnetic memory, etc. ReRAM stands out due to its potential for high density, fast switching speeds, low power consumption, and simple two-terminal capacitor-like structure8,9,10. Moreover, these devices exhibit high potential for neuromorphic computing due to their ability to emulate synaptic behavior, such as analog resistance modulation and spike-timing-dependent plasticity4,11,12,13. Here, inorganic materials, particularly transition metal oxides (TMOs) come into the picture as the active material for ReRAM, because of their excellent resistive switching ability, flexible stoichiometry, and ability to integrate seamlessly with the standard manufacturing techniques used in producing complementary metal oxide semiconductor (CMOS) devices14,15,16. Materials such as tantalum oxide (Ta2O5), hafnium oxide (HfO2), and gallium oxide (Ga2O3) have been extensively studied for their high thermal stability, scalability, and the ability to undergo reversible resistive switching (RS)17,18,19. Recent advancements in ReRAM devices based on these inorganic materials have led to substantial improvements in device performance, including enhanced switching speeds and increased endurance17,19. However, perfect crystallinity of these materials is not a requirement for resistive switching as several amorphous oxides have shown resistive switching characteristics20,21,22,23. As eloquently stated by Bulja et al., “The defects in TMOs should not be viewed as undesirable structures for the achievement of perfect RS; rather, the goal should lie in forming/engineering “perfect” imperfections with the aim of achieving high dynamic ratios, high switching speeds and excellent electrical conductivity”24. Along this idea, this research work has considered amorphous NiO as the active layer.After the active material, the most important component of a ReRAM device is its substrate which could impart flexibility and transparency for aesthetic wearable electronics, real-time health monitors, etc25,26. Polyethylene Terephthalate (PET or Pet) substrate with its optimal bending radius, light weight, and optical transparency has been explored in research as a flexible substrate6. This makes it particularly beneficial for portable and wearable electronics, enabling the fabrication of bendable and stretchable devices. However, traditionally, metals like Pt, Al, Cu, etc. have been used as bottom electrodes, which not only hinders the mechanical flexibility and optical transparency of the device but also is costly in terms of both money and energy27,28,29,30. In contrast to metal electrodes, metal oxide electrodes like fluorine tin oxide and indium tin oxide enable some flexibility and transparency with enhanced scalability. However, cost reduction of the system can be achieved if instead of rare and expensive elements like indium and tin, abundant and non-toxic elements like aluminium and zinc are used in transparent conductive oxides. In this regard, aluminium-doped zinc oxide can achieve comparable or superior electrical conductivity through optimized doping and deposition conditions, providing low resistivity values suitable for transparent electrodes31,32,33. Moreover, AZO with its less mechanical brittleness offers fewer cracks and device failure on bending34.In this research, we explore the resistive switching characteristics of NiO thin films sputtered on AZO-coated PET substrate with Ti as the top electrode. The Ti/NiO/AZO/PET device exhibited good bipolar resistive switching characteristics, transitioning from an HRS to LRS at a VSET of ~ 5.4 V and returning to HRS at a VRESET of -2.9 V. The current-voltage (I-V) characteristics reveal that the conduction in the HRS follows ohmic behavior at low voltages and transitions to SCLC and then to trap-filled-limited (TFL) conduction as the voltage increases. This behavior is attributed to the density of injected carriers surpassing the density of available traps within the NiO layer. The device demonstrated reliable performance under mechanical stress, maintaining stable switching parameters even after being subjected to bending with radii of 10 and 15 mm. These results are significant for the development of flexible, transparent, and high-density data storage applications.MethodsSynthesis of AZO nanoparticlesThe AZO nanoparticles (NPs) were synthesized using a precipitation method. Initially, 0.2 M zinc acetate dihydrate was dissolved in 40 ml of deionized (DI) water at 50 °C under continuous stirring. Aluminium nitrate nonahydrate (Al(NO3)3·9H2O) was then introduced as the aluminium doping agent, maintaining a 2% molar ratio of Al3+ to Zn2+. 0.4 M NaOH solution was mixed into the precursor solution under continuous stirring at 50 °C until complete precipitation. This precipitate was washed three times with ethanol to remove any residual impurities and subsequently calcined at 500 °C for 60 min to obtain AZO NPs.Fig. 1Schematic showing the device fabrication.Full size imageFabrication of ReRAM deviceThe ReRAM device was fabricated by first depositing a thin film (~ 70 nm) of the synthesized AZO NPs onto a PET substrate via spray coating. This layer served as the bottom electrode. Subsequently, a thin layer (~ 130 nm) of NiO film was deposited on top of the AZO layer using radio-frequency (RF) magnetron sputtering. This process utilized a NiO target, a pressure of 10− 2 mbar, an argon environment, and an applied power of 100 W. Finally, a top electrode of titanium (Ti) (50 nm thickness) was deposited by an e-beam evaporator (1Å/min) in a vacuum of 5 × 10− 6 mbar, through a shadow mask to complete the device structure. The schematic of the device fabrication is shown in Fig. 1.Characterizations and measurementsThe film thickness was determined using a stylus profilometer. Subsequently, the phase composition of the samples was confirmed through X-ray diffraction (XRD) analysis. The transparency of the film was assessed via ultraviolet-visible (UV-vis) absorption spectroscopy. The morphological investigation and elemental mapping were performed using a scanning electron microscope (SEM, JEOL-JSM 6510LV) equipped with energy-dispersive X-ray (EDX). Finally, the electrical properties of the ReRAM devices were characterized using a Keithley semiconductor parameter analyzer (using a Keithley 2400 source meter) connected to a probe station. The voltage sweep mode was used to perform switching measurement, with the bias considered positive for the electrical current flowing from the Ti electrode to the AZO electrode. The device was kept from experiencing a permanent breakdown by using a compliance current of 1 mA.Results and discussionThe XRD pattern of the NiO/AZO/PET sample is presented in Fig. 2 (a). The XRD spectra distinctly display the peaks corresponding to AZO, which indicates the crystalline structure of the AZO layer35. However, no clear peaks corresponding to NiO are observed in the spectra. This absence of distinct NiO peaks suggests that the as-deposited NiO thin film without any treatment is amorphous in nature.Fig. 2(a). XRD spectra of NiO/AZO thin film on PET substrate (b) Transmission spectra, inset show Raman spectra of NiO/AZO thin film on PET substrate (c) SEM image of the NiO/AZO/PET film with the EDX spectrum and corresponding elemental mapping.Full size imageMoreover, the optical transmittance using UV-Vis spectroscopy was measured for the NiO/AZO /PET layer and a transmittance of over 75% in the visible region (400 –800 nm) could be achieved, as shown in Fig. 2 (b). Raman analysis was used to characterize the thin films of NiO and AZO deposited on the PET substrate. As shown in the inset of Fig. 2 (b), peaks corresponding to NiO, AZO, and PET substrate can be discerned. The first four peaks at ~ 150, 200, 300, and 450 cm− 1 can be matched respectively to E2(low), 2E1(low), E2(high)-E2(low), E2(high) peaks of AZO36,37. The most prominent peak at 500 cm− 1 can be attributed to the first-order longitudinal optical (LO) mode of NiO38,39. Another peak at 800 cm− 1 can be assigned to the second-order transverse mode (2TO) of NiO40. All other peaks can be directly matched to different carbon groups found in PET substrate as clearly marked in the inset of Fig. 2 (b)41,42. The SEM image of the film along with the EDX spectrum and mapping is shown in Fig. 2 (c). A uniform deposition for the film can be seen with mapping confirming the presence of zinc, aluminium, nickel, and oxygen in the device.The I-V characteristics of the as-grown Ti/NiO/AZO/PET device were investigated by sweeping the voltage in a sequence of 0 V → 6 V → 0 V → -6 V → 0 V. The inset in Fig. 3 (a) presents the schematic structure of the device. Figure 3 (a) shows the forming free bipolar resistive switching I-V characteristics on the linear and semilogarithmic scales, along with the corresponding resistance-voltage characteristics. It can be observed that the device displays a counterclockwise BRS behaviour. The device starts with a high resistance state and there is a gradual increase in current with the increasing voltage and finally, the device switches to a low resistance state at VSET = ~ 5.4 V. The device remains in the LRS state even after the applied voltage is removed (0 V) and switches backed to HRS at VRESET = ~ 2.9 V during the negative voltage sweep. The resistive switching behaviour is attributed to oxygen vacancies, which play a crucial role in the switching mechanism. Oxygen vacancies are recognized as the primary conduction mechanism in TMOs43.Fig. 3(a) Current-voltage curve of the resistive memory device in Ti/NiO/AZO/PET structure. The right inset shows the schematic of the fabricated Ti/NiO/AZO/PET device. The left inset shows the semi-logarithmic current-voltage and resistance-voltage characteristics of the device. (b) The I–V curve of the flexible resistive memory device in Ti/NiO/AZO/PET structure at different bending radii. (c) The I–V curve of the flexible device showing the cycle-to-cycle switching data.Full size imageThe resistive switching in our Ti/NiO/AZO device is primarily driven by the migration of oxygen vacancies within the NiO layer. In p-type materials like NiO, oxygen vacancies serve as acceptors or electron traps, which significantly influence their conduction properties44. During the SET process, when a positive bias is applied to the top electrode (Ti), oxygen vacancies migrate away from the Ti/NiO interface toward the NiO/AZO layer. This migration reduces the effective barrier height at the Ti/NiO interface, allowing for the formation of a continuous conductive filament through the NiO layer. This filament facilitates conduction and transitions the device to the low-resistance state at a set voltage of ~ 5.4 V. However, during the RESET process, applying a negative voltage drives oxygen vacancies back toward the Ti/NiO interface. This increases the vacancy concentration near the interface, causing local band bending and enhancing the effective barrier height. As a result, the current flow is limited, and the device transitions back to the high-resistance state at a reset voltage of ~ 2.9 V. Similar working mechanisms were also reported by Chabungam et al. and Ryu et al. in their ReRAM study44,45. To demonstrate the bending effect of the device, the I-V characteristics were measured under different bending radii of 10 and 15 mm. The device was subjected to bending stress for 30 min and then returned to a flat state to release the tensile stress. As shown in Fig. 3 (b), the VSET and VRESET values remained almost the same as before bending. Figure 3 (c) shows the cycle-to-cycle variability from the 1st to the 400th cycle, showing almost negligible variation.Fig. 4Linear fitting of the I-V characteristic curve of the device in (a) positive and (b) negative region for the HRS and LRS.Full size imageIn order to investigate the resistive switching mechanism of the device in the two resistive states, the I-V characteristics of the positive and negative regions were replotted on a log-log scale, as depicted in Fig. 4 (a) and (b). In both biasing conditions, the HRS is characterized by three fitted curves: ohmic conduction, SCLC, and TFL current. As illustrated in Fig. 5 (a), at low voltage (V < Vtr), the density of injected carriers is significantly lower than the density of traps (oxygen vacancies).Fig. 5(a-c). Schematic representation of the resistive switching mechanism.Full size imageConsequently, the likelihood of carrier trapping is diminished, and the majority of traps remain unoccupied. In this condition, the traps do not significantly impact the conduction process, and the concentration of free carriers dominates over the injected carriers46. The free carriers move easily through the NiO under the influence of the applied electric field, following a linear relationship I α V.When the applied voltage increases (Vtr < V < VTFL), as shown in Fig. 5 (b), the density of injected carriers becomes strong enough to inject a significant number of carriers from the electrodes into the NiO. In this condition, the injected carrier density becomes much higher than the free carriers, creating a space charge region. Some of the injected carriers get trapped by the defects within the NiO. The current in this condition follows a superlinear relationship with voltage as I α Vm where m is equal to greater than 2. As the applied voltage further increases (V > VTFL), all the available traps in the NiO get filled by the injected carriers and can no longer capture additional carriers, leading to higher current flow, as shown in Fig. 5 (c). Beyond VTFL, the current is no longer limited by the traps but by the injected carrier density, transitioning from SCLC to the trapped-filled limited SCLC region. The current follows a superlinear relationship with the voltage as I α Vn where n is greater than m in the SCLC region46,47. When the device switches from the HRS to the LRS, ohmic conduction dominates the carrier transport due to the formation of conducting filaments by oxygen vacancies.Fig. 6(a) Endurance (b) Retention property of the fabricated memory device at a read at 1 V, at Room temperature (c) The cumulative probability of HRS and LRS (d) HRS-LRS window for different bending radii.Full size imageIn the negative region, the device maintains the LRS and the conduction is mainly due to ohmic conduction. However, as the negative bias increases, oxygen vacancies begin to move away from the interface. This movement of vacancies decreases the number of available conducting paths, which in turn increases the resistance and changes the device back to the HRS.To test the reliability characteristics of the devices, endurance, and data retention measurements were conducted. Figure 6 (a) shows the endurance test results for the device with a read voltage of + 1 V for 400 cycles. The device exhibits a stable HRS and LRS ratio, as indicated by linear fitting in Fig. 6 (a). Figure 6 (b) shows the retention characteristics of the device when read at + 1 V. The device remains stable and reliable for more than 103 sec. The HRS/LRS resistances, as shown in Fig. 6 (c) for different bending radii, demonstrate that the RS performance is scarcely affected by bending with different bending radii. Furthermore, the cumulative distribution of the LRS and HRS, as shown in Fig. 6 (d), demonstrates good uniformity and stability, with the coefficient of variations estimated to be 13.2% and 9.7%, respectively. The performance of different reported ReRAM devices is compared with this work and presented in Table 1.Table 1 The performance of different ReRAM devices.Full size tableConclusionIn this study, we demonstrated the fabrication and characterization of a flexible and forming-free ReRAM device using an aluminium-doped zinc oxide electrode and an amorphous NiO active layer on a PET substrate. The Ti/NiO/AZO/PET device exhibited excellent bipolar resistive switching behavior, maintaining stability under mechanical bending conditions, which is crucial for flexible electronics applications. Our structural analysis revealed the amorphous nature of the as-deposited NiO film, which, upon annealing, transitioned to a crystalline phase. The optical transparency of over 75% in the visible region, combined with the flexibility and mechanical resilience of the device, underscores its suitability for integration into transparent and wearable electronic systems. The electrical characterization indicated reliable resistive switching with a clear distinction between HRS and LRS, driven by the formation and rupture of conductive filaments composed of oxygen vacancies. The device showed forming-free bipolar resistive switching with a set voltage of ~ 5.4 V and a reset voltage of ~ 2.9 V. Importantly, the switching mechanism was unaffected by bending radii, highlighting the robustness of the AZO electrode in maintaining device integrity. Endurance and retention tests confirmed the device’s stability and reliability, with consistent HRS/LRS ratios for 400 cycles and data retention exceeding 103 seconds. The coefficient of variations for LRS and HRS were 13.2% and 9.7%, respectively, demonstrating good uniformity and performance. Overall, the integration of AZO electrodes with NiO active layers presents a promising approach for developing high-density, and mechanically flexible memory devices, which are critical for next-generation wearable and portable electronics.
Data availability
The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
ReferencesIelmini, D. & Wong, H. S. P. In-memory computing with resistive switching devices. Nat. Electron. 1(6), 333–343 (2018).Adiba, A., Pandey, V., Ahmad, T., Nehla, P. & Munjal, S. Multilevel resistive switching with negative differential resistance in Al/NiO/ZnFe2O4/ITO ReRAM device. Phys. B Condens. Matter. 654, 414742 (2023).Article
CAS
Google Scholar
Beyond von Neumann. Nat. Nanotechnol. 15(7), 507–507 (2020).Zhou, G. et al. Full hardware implementation of neuromorphic visual system based on multimodal optoelectronic resistive memory arrays for versatile image processing. Nat. Commun. 14(1), 1–11 (2023).Wang, T. et al. Reconfigurable neuromorphic memristor network for ultralow-power smart textile electronics. Nat. Commun. 13(1), 1–8 (2022).Yang, C. et al. A multimodal perception-enabled flexible memristor with combined sensing-storage-memory functions for enhanced artificial injury recognition. Small 2402588 https://doi.org/10.1002/SMLL.202402588 (2024).Han, T. et al. Fully 2D materials-based resistive switching circuits for advanced data encryption. Adv. Funct. Mater. 2403029 https://doi.org/10.1002/ADFM.202403029 (2024).Phadke, O., Saraswat, V. & Ganguly, U. Highly deterministic one-shot set-Reset Programming Scheme in PCMO Resistive Random-Access memory. ACS Appl. Electron. Mater. 4, 4921–4928 (2022).Article
CAS
Google Scholar
Rajarathinam, S., Panwar, N., Kumbhare, P., Ganguly, U. & Venkataramani, N. Bipolar resistive switching with improved memory window in W/ZnFe2O4/Pt devices. Mater. Sci. Semicond. Process. 142, 106497 (2022).Article
CAS
MATH
Google Scholar
Anwer, S. et al. Cobalt oxide nanoparticles embedded in borate matrix: A conduction mode atomic force microscopy approach to induce nano-memristor switching for neuromorphic applications. Appl. Mater. Today. 29, 101691 (2022).Article
MATH
Google Scholar
Park, J. et al. Multi-level, forming and filament free, bulk switching trilayer RRAM for neuromorphic computing at the edge. Nat. Commun. 15(1), 1–11 (2024).Aguirre, F. et al. Hardware implementation of memristor-based artificial neural networks. Nat. Commun. 15(1), 1–40 (2024).Kim, S. J. et al. Linearly programmable two-dimensional halide perovskite memristor arrays for neuromorphic computing. Nat. Nanotechnol. 2024, 1–10. https://doi.org/10.1038/s41565-024-01790-3 (2024).Article
CAS
Google Scholar
Abbas, Y. et al. Compliance-free, digital SET and analog RESET synaptic characteristics of sub-tantalum oxide based neuromorphic device. Sci. Rep. 8, 1–10 (2018).Kwon, S., Kim, M. J., Lim, D. H., Jeong, K. & Chung, K. B. Controlling resistive switching behavior in the solution processed SiO2-x device by the insertion of TiO2 nanoparticles. Sci. Rep. 12(1), 1–11 (2022).Adiba, A., Khan, M. A. & Ahmad, T. Unveiling the potential of NiO–ZnCo2O4 nano-composites: Electrical, optical, electrochemical and antibacterial investigation. Heliyon 10, e34880 (2024).Article
CAS
PubMed
PubMed Central
Google Scholar
D’Agostino, S. et al. DenRAM: Neuromorphic dendritic architecture with RRAM for efficient temporal processing with delays. Nat. Commun. 15(1), 1–12 (2024).Dai, X., Zhang, X., Gong, D. & Xiang, G. Performance enhancement and in situ Observation of Resistive switching and magnetic modulation by a tunable two-level system of Mn dopants in a-Gallium oxide-based Memristor. Adv. Funct. Mater. 33, 2304749 (2023).Article
CAS
Google Scholar
Török, T. N., Makk, P., Balogh, Z., Csontos, M. & Halbritter, A. Quantum Transport Properties of Nanosized Ta2O5 Resistive switches: Variable Transmission Atomic synapses for Neuromorphic Electronics. ACS Appl. Nano Mater. 6, 21340–21349 (2023).Article
Google Scholar
Huang, Y. et al. Amorphous ZnO based resistive random access memory. RSC Adv. 6, 17867–17872 (2016).Article
ADS
CAS
Google Scholar
Munde, M. S. et al. Intrinsic resistance switching in amorphous silicon suboxides: The role of columnar microstructure. Sci. Rep. 7(1), 1–7 (2017).Jang, B., Kim, J., Lee, J., Jang, J. & Kwon, H. J. Stable switching behavior of low-temperature ZrO2 RRAM devices realized by combustion synthesis-assisted photopatterning. J. Mater. Sci. Technol. 189, 68–76 (2024).Article
CAS
MATH
Google Scholar
Jeong, D. G. et al. Grain boundary control for high-reliability HfO2-based RRAM. Chaos Solitons Fractals. 183, 114956 (2024).Article
MATH
Google Scholar
Bulja, S. et al. High frequency resistive switching behavior of amorphous TiO2 and NiO. Sci. Rep. 12(1), 1–16 (2022).Son, D. et al. Multifunctional wearable devices for diagnosis and therapy of movement disorders. Nat. Nanotechnol. 9(5), 397–404 (2014).Zhu, M., He, T. & Lee, C. Technologies toward next generation human machine interfaces: From machine learning enhanced tactile sensing to neuromorphic sensory systems. Appl. Phys. Rev. 7, 031305 (2020).Shang, J. et al. Highly flexible resistive switching memory based on amorphous-nanocrystalline hafnium oxide films. Nanoscale 9, 7037–7046 (2017).Article
CAS
PubMed
MATH
Google Scholar
Tian, X. et al. Printable and flexible Planar Silver electrodes-based resistive switching sensory array. Front. Sens. 1, 600185 (2020).Article
Google Scholar
Du, H. et al. Engineering Silver Nanowire networks: From transparent electrodes to Resistive Switching devices. ACS Appl. Mater. Interfaces. 9, 20762–20770 (2017).Article
CAS
PubMed
Google Scholar
Xue, D. et al. Flexible resistive switching device based on the TiO2 nanorod arrays for non-volatile memory application. J. Alloys Compd. 822, 153552 (2020).Article
CAS
Google Scholar
Li, Y. et al. Enhanced performance in Al-Doped ZnO Based Transparent Flexible Transparent Thin-Film transistors due to Oxygen Vacancy in ZnO Film with Zn-Al-O interfaces fabricated by atomic layer deposition. ACS Appl. Mater. Interfaces. 9, 11711–11720 (2017).Article
CAS
PubMed
MATH
Google Scholar
Zhao, H. L. et al. Impact of pre-annealing process on electrical properties and stability of indium zinc oxide thin-film transistors. Sci. Rep. 12, 1–7 (2022).Van Toan, N., Tuoi, T. T. K., Inomata, N., Toda, M. & Ono, T. Aluminum doped zinc oxide deposited by atomic layer deposition and its applications to micro/nano devices. Sci. Rep. 11(1), 1–12 (2021).Choi, H. R., Eswaran, S. K., Lee, S. M. & Cho, Y. S. Enhanced fracture resistance of flexible ZnO:Al Thin films in situ sputtered on Bent Polymer substrates. ACS Appl. Mater. Interfaces. 7, 17569–17572 (2015).Article
CAS
PubMed
Google Scholar
Mazumder, J. A. et al. Biomimetic green synthesis of ZnO nanoflowers using α-amylase: From antimicrobial to toxicological evaluation. Sci. Rep. 14(1), 1–11 (2024).Wang, C. C. et al. Zinc oxide nanostructures enhanced photoluminescence by carbon-black nanoparticles in Moiré heterostructures. Sci. Rep. 13, 9704 (2023).Article
ADS
CAS
PubMed
PubMed Central
Google Scholar
Calzolari, A. & Nardelli, M. B. Dielectric properties and Raman spectra of ZnO from a first principles finite-differences/finite-fields approach. Sci. Rep. 3, 2999 (2013).Article
ADS
PubMed
PubMed Central
MATH
Google Scholar
Lin, Z., Du, C., Yan, B., Wang, C. & Yang, G. Two-dimensional amorphous NiO as a plasmonic photocatalyst for solar H2 evolution. Nat. Commun. 9, 4036 (2018).Article
ADS
PubMed
PubMed Central
MATH
Google Scholar
Adiba, A., Meitei, P. N. & Ahmad, T. Laser-induced modulation of Magnon and Phonon excitations: Size and defect dependency in antiferromagnetic NiO nanoparticles with rhombohedral distortion. Next Nanatechnol. 7, 100098 (2025).Article
Google Scholar
Adiba, A., Waris, Munjal, S., Khan, M. Z. & Ahmad, T. Piezo-photocatalytic degradation of organic pollutant by a novel BaTiO3–NiO composite. Eur. Phys. J. Plus. 138, 408 (2023).Article
CAS
Google Scholar
González-Córdova, J. A. et al. Optical anisotropy Raman response of polyethylene terephthalate strained thin films. Phys. B Condens. Matter 654 (2023).Zuo, Z. et al. Transparent, flexible surface enhanced Raman scattering substrates based on Ag-coated structured PET (polyethylene terephthalate) for in-situ detection. Appl. Surf. Sci. 379, 66–72 (2016).Article
ADS
CAS
Google Scholar
Sawa, A. Resistive switching in transition metal oxides. Mater. Today. 11, 28–36 (2008).Article
CAS
MATH
Google Scholar
Chabungbam, A. S. et al. Oxygen vacancy-controlled forming-free bipolar resistive switching in Er-doped ZnO memristor. Appl. Surf. Sci. Adv. 25, 100675 (2025).Article
Google Scholar
Ryu, J., Park, K., Sahu, D. P. & Yoon, T. S. Forming-free low-voltage, and high-speed resistive switching in Ag/oxygen-deficient vanadium oxide(VOx)/Pt device through two-step resistance change by Ag filament formation. ACS Appl. Mater. Interfaces. 16, 26450–26459 (2024).Shen, X. et al. Effect of crystallinity on the performance of AlN-based resistive random access memory using rapid thermal annealing. Appl. Phys. Lett. 118 (2021).Hsu, C. C., Lin, Y. S., Cheng, C. W. & Jhang, W. C. Annealing effect on the performance of copper Oxide Resistive Memory devices. IEEE Trans. Electron. Devices. 67, 976–983 (2020).Article
ADS
CAS
MATH
Google Scholar
Desai, T. R., Goud, R. S. P., Dongale, T. D. & Gurnani, C. Evaluation of Nanostructured NiS2 Thin films from a single-source precursor for flexible Memristive devices. ACS Omega. 8, 48873–48883 (2023).Article
CAS
PubMed
PubMed Central
Google Scholar
Garlapati, S. K. et al. Compliance-free, analog RRAM devices based on SnOx. Sci. Rep. 14(1), 1–8 (2024).Wang, B. et al. Resistive switching in Ga- and Sb-doped ZnO single nanowire devices. J. Mater. Chem. C Mater. 3, 11881–11885 (2015).Article
CAS
MATH
Google Scholar
Gora, S. et al. Asymmetric resistive switching by anion out-diffusion mechanism in transparent Al/ZnO/ITO heterostructure for memristor applications. Surf. Interfaces. 30, 101950 (2022).Article
CAS
MATH
Google Scholar
Komal, K., Singh, M. & Singh, B. Flexible SnO2–MoS2 based memristive device exhibiting stable and enhanced memory phenomenon. J. Phys. D Appl. Phys. 57, 105107 (2023).Article
ADS
MATH
Google Scholar
Salonikidou, B. et al. Na+-doped WO3 double-layer resistive switching device for biomimetic applications. Appl. Mater. Today. 41, 102515 (2024).Article
MATH
Google Scholar
Download referencesAcknowledgementsAA acknowledges CSIR for providing the Senior Research Fellowship. AA also acknowledges IIT Delhi for providing access to characterization facilities.Author informationAuthors and AffiliationsDepartment of Physics, Aligarh Muslim University, Aligarh, 202002, IndiaAdiba Adiba & Tufail AhmadCentre for Nanotechnology, IIT Guwahati, Guwahati, 781039, IndiaPh Nonglen MeiteiAuthorsAdiba AdibaView author publicationsYou can also search for this author in
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PubMed Google ScholarContributionsA.A: Methodology, Visualization, Investigation, Formal analysis, Conceptualization, Writing, Editing, Software, Data curation.P.N.M: Software, Analysis, Writing, Editing, Conceptualization, Validation.T.A: Resources, Supervision, Editing.All authors reviewed the manuscript.Corresponding authorCorrespondence to
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Sci Rep 15, 8165 (2025). https://doi.org/10.1038/s41598-025-88549-5Download citationReceived: 26 August 2024Accepted: 29 January 2025Published: 10 March 2025DOI: https://doi.org/10.1038/s41598-025-88549-5Share this articleAnyone you share the following link with will be able to read this content:Get shareable linkSorry, a shareable link is not currently available for this article.Copy to clipboard
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KeywordsResistive switchingNiOTransparent conducting oxidesOhmicSpace charge limited conductionTrap filled limited conduction