Oxidation of graphene 'bow tie' nanofuses for permanent, write-once-read-many data storage devices

Halide Perovskites: A New Era of Solution-Processed Electronics

Organic-inorganic mixed halide perovskites have emerged as an excellent class of materials with a unique combination of optoelectronic properties, suitable for a plethora of applications ranging from solar cells to light-emitting diodes and photoelectrochemical devices. Recent works have showcased hybrid perovskites for electronic applications through improvements in materials design, processing, and device stability. Herein, a comprehensive up-to-date review is presented on hybrid perovskite electronics with a focus on transistors and memories. These applications are supported by the fundamental material properties of hybrid perovskite semiconductors such as tunable bandgap, ambipolar charge transport, reasonable mobility, defect characteristics, and solution processability, which are highlighted first. Then, recent progresses on perovskite-based transistors are reviewed, covering aspects of fabrication process, patterning techniques, contact engineering, 2D versus 3D material selection, and device performance. Furthermore, applications of perovskites in nonvolatile memories and artificial synaptic devices are presented. The ambient instability of hybrid perovskites and the strategies to tackle this bottleneck are also discussed. Finally, an outlook and opportunities to develop perovskite-based electronics as a competitive and feasible technology are highlighted.

Five-Dimensional Optical Data Storage Based on Ellipse Orientation and Fluorescence Intensity in a Silver-Sensitized Commercial Glass

Five-dimensional (5D) recording and decoding is demonstrated by using femtosecond direct laser writing in a silver-containing commercial glass. In particular, laser intensities and ellipse orientations generated by anamorphic focusing are employed to produce 5D data storage unit (3D for XYZ, 1D for the orientation of the elliptically-shaped data storage unit and 1D for its fluorescence intensity). In the recording process, two different images of a 4-bit bitmap format were simultaneously embedded in the medium by multiplexing the elliptical orientation of the laser focus and its intensity so as to access oriented elliptical patterns with independent fluorescence intensity. In the decoding process, two merged original images were successfully reconstructed by comparing each data storage unit with a fabricated calibration matrix of 16 × 16 levels for elliptic orientations and fluorescence intensities. We believe this technique can be applied to semi-permanent high-density data storage device.

Structural colour QR codes for multichannel information storage with enhanced optical security and life expectancy

Current schemes for encoding and decoding anticounterfeiting optical quick response (QR) codes involve miscellaneous challenges. The need for using multiple light sources to read out the wavelength-multiplexed data from optically encoded organic dyes, photoblinking from quantum dots, and autofluorescence from carbon dots are some typical examples. In order to address these restrictions, we exploited our previously devised nanoimprinting-exposure-thermal-treatment (NETT) data storage approach to present a new structural-colour-based regime for optical encoding of high-security QR codes. The angle-dependent readability of our diffraction-based nanostructures poses an enhanced optical security feature that can substitute the existing inefficient encoding strategies by eliminating the constraints associated with them. Additionally, in comparison with conventional optical encoding media, using the long-lasting photocrosslinked SU-8 in the NETT method considerably enhances the life expectancy of the proposed QR codes. Also, considering the rapid NETT-based Ni stamp origination method, which was previously introduced by our group, mass-generation of the proposed codes is feasible. Owing to the special optically variable effects provided by the nanostructures, duplication of our QR codes is very difficult. The colour code design, which embeds 766 characters in 2907 modules in red, green and blue channels, was generated and fabricated onto generic nanostructure arrays using the NETT process. The encoded information was successfully read out from the pattern using a broadband light source and a digital camera. Higher capacities are also deemed to be reachable by implementing image processing and machine learning algorithms to overcome in-channel module recognition and cross-channel interferences.

Thin-Film Carbon Nanofuses for Permanent Data Storage

In this study, we have fabricated nanofuses from thin-film, arc-deposited carbon for use in permanent data storage. Thin-film carbon fuses have fewer fabrication barriers and retain the required resistivity and structural stability to act as a data-storage medium. Carbon thin films were characterized for their electrical, microstructural, and chemical bonding properties. Annealing these films in an argon environment at 400 °C reduced the resistivity from about 4 × 10^-2 Ω cm as deposited to about 5 × 10^-4 Ω cm, allowing a lower blowing voltage. Nanofuses with widths ranging from 200 to 60 nm were fabricated and tested. They blow with voltages between 2 and 5.5 V, and the nanofuses remain stable in both "1" and "0" states under a constantly applied read voltage of 1 V for over 90 h.