Trap‐Related Nonvolatile Negative Photoconductivity in a Single Ag@Al₂O₃ Hybrid Nanorod for a Photomemory with Light‐Writing and Bias‐Erasing

Abstract

For zero band‐gap metal Ag and ultrawide band‐gap Al2O3, it is difficult to produce impressive photoresponse to visible light due to the limitation of energy gaps. Herein, it is demonstrated that individual Ag@Al2O3 hybrid nanorods, synthesized by a two‐stage hydrothermal method and followed by thermal reduction annealing, can show excellent negative photoconduction of about 400 nm violet and 800 nm near‐infrared lights at room temperature. Moreover, the light‐induced high resistance state (HRS) is well maintained at relatively low operation bias after the removal of illumination, indicative of a nonvolatile memory effect. More importantly, the device is back to its initial low resistance state (LRS) after subsequently being applied a relatively large bias, suggestive of an erasable effect with large bias. In the hybrid nanorods, Ag nanoparticles serve as trap centers and can capture and store charges. Under the illumination of sub‐band‐gap light, trapped charges are excited, resulting in an HRS due to emptying the traps. On the contrary, a large external electric field triggers charges to be injected into traps in dark, resulting in an LRS. Regarding a superior negative photoswitching with light‐writing and bias‐erasing memory, Ag@Al2O3 nanohybrids have a tremendous potential in optical sensors and nonvolatile photomemory applications.

Optically Modulated Threshold Switching in Core–Shell Quantum Dot Based Memristive Device

“…The decrease in conductivity of HRS under light illumination may be attributed to the decrease of charge filling level in traps (Figure S10 in the Supporting Information). [ 59 ] The light intensity has little impact on the operation voltage (Figure S11 in the Supporting Information). Particularly, the effect of optically modulated threshold switching is closely related to irradiation wavelength.…”

Giant Piezoresistive Effect of CdS@C Hybrid Nanobelts for Volatile Real-Time Sensor and Erasable Nonvolatile Memory to Stress

“…It can be expected that a strong interface coupling effect can take place between two nanostructures owing to the existence of affluent surface states. , In addition, QDs can form effective trap centers, and the filling of trap level is tunable. Therefore, some novel properties are likely to appear. , For carbon materials, they can generally show superior conductive properties, and furthermore, they can show a PZR effect as well. − Therefore, it is more suitable as a matrix of a hybrid composite structure to build high-performance GPZR materials. For the nanostructure with one-dimension (1D), in addition, it is extremely beneficial to build a single nanostructure-based two-terminal device, and thus, it is very easy for the actual physical mechanism to be well-identified by the simple configuration in comparison with nanostructure assemblies. − Accordingly, it is more appropriate for an individual 1D nanostructure to serve as a building block to directly construct a nanodevice.…”

“…Therefore, some novel properties are likely to appear. 40,41 For carbon materials, they can generally show superior conductive properties, and furthermore, they can show a PZR effect as well. 42−45 Therefore, it is more suitable as a matrix of a hybrid composite structure to build high-performance GPZR materials.…”

Ag Nanoparticle-Decorated WO3 Nanowires for Nonvolatile Memory

“…10 Ji et al also reported that clustering of Ag formed a deep trap level, which captured charges effectively. 14 Park et al mentioned that the use of NPs obtained better endurance characteristics and increased memory window. 15 On the other hand, NPs reduce the influence of traps at the interface of NPs/metal oxide nanostructures.…”

“…Choi et al reported Ag NPs decorated on Si NWs which served as stable charge trapping sites, and the improvement of the retention was explained by the incorporation of Ag NPs to charge trapping . Ji et al also reported that clustering of Ag formed a deep trap level, which captured charges effectively . Park et al mentioned that the use of NPs obtained better endurance characteristics and increased memory window .…”