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Vision sensors are becoming increasingly ubiquitous, and they continuously collect, store, communicate, and process vast amount of sensitive data that are vulnerable to being stolen and misused. Existing cryptosystems based on complex cipher algorithms generally require extensive computational resources, making them difficult to use in vision sensors that have limited processing capabilities. Here, we propose and experimentally demonstrate a novel in situ image cryptography scheme based on a neuromorphic vision sensor comprising all-optically controlled (AOC) memristors. Due to the unique light wavelength and irradiation history-dependent bidirectional persistent photoconductivity of AOC memristors, a visual image can be stored, encrypted, decrypted, denoised, and destroyed within a vision sensor. A decrypted image can be encoded in situ and then accurately recognized through a memristive neural network. Encrypted and destroyed images are capable of withstanding hacking attacks even with trained neural networks. Our cryptography scheme enables complete cryptographic operations entirely on a sensor and, therefore, effectively safeguards visual information. This work provides a simple yet efficient solution to the security challenges faced by vision sensors. [ABSTRACT FROM AUTHOR]

Traditional memristors based on metal/insulator/metal sandwich structures generally require the operation voltages of several volts to switch the device between different resistance states. In this work, we report the ultralow set and reset voltages of 14 mV and 0.3 V in a simple bilayer device, respectively, which is composed of the widely used indium tin oxide (ITO) solely. Such low operation voltages might be ascribed to the synergistic effect of the loose porous structure in the upper ITO layer deposited by electron beam evaporation, the amorphous interface between two ITO layers, and the formation of an oxygen concentration gradient triggered by an initiation process. Based on the superior resistive switching properties of this kind bilayer device, synaptic functions and image memorization are achieved by applying ultralow electrical stimulus. The prototype device not only paves the way for simplifying the device structure and the fabrication process but also offers possibilities to develop transparent multifunctional devices with low power consumption. [ABSTRACT FROM AUTHOR]

A comparison of the asymmetric OFF-state current-voltage characteristics between Cu/ZnO/Pt and Cu/ZnO/Al-doped ZnO (AZO) electrochemical metallization memory (ECM) cells demonstrates that the Cu filament rupture and rejuvenation occur at the ZnO/Pt (or AZO) interface, i.e., the cathodic interface. Therefore, the filament is most likely to have a conical shape, with wider and narrower diameters formed at the anodic and cathodic interfaces, respectively. It is inferred that the filament growth starts at the anode surface and stops at the cathode surface. Our results indicate that oxide-based ECM cells strongly differ from sulfide- and selenide-based ones in the resistive switching mechanism. [ABSTRACT FROM AUTHOR]

Ambipolar thin film transistors have attracted increasing research interests due to their promising applications in complementary logic circuits and the dissipative charge transporting devices. Here, we report the fabrication of an ambipolar transistor using tin mono-oxide (SnO) as a channel, which possesses balanced electron and hole field-effect mobilities. A complementary metal oxide semiconductor-like inverter using the SnO dual operation transistors is demonstrated with a maximum gain up to 30 and long-term air stability. Such logic device configuration would simplify the circuit design and fabrication process, offering more opportunities for designing and constructing oxide-based logic circuits. [ABSTRACT FROM AUTHOR]