Resistive switching is observed in a single SnO2 nanowire device with two back-to-back Schottky diodes. The underlying mechanism can be well interpreted by the switchable diode effect, which is caused by tunable Schottky barrier heights due to the drift of charged defects induced by external electrical field. A resistance window of more than 3 orders of magnitude has been achieved. The device also shows excellent performance in endurance and retention time. Additionally, a very small current under negative bias is observed, which can avoid the sneaking current induced in the nearby devices. Due to the greatly reduced device size, power consumption, and inherent nature of Schottky diode, the work presented here should be useful for the development of high density circuitries.

The first electrically driven random laser diode with nonvolatile resistive random access memory functionality is designed and demonstrated. To illustrate the working principle, a metal–insulator–semiconductor structure based on Pt/MgO/ZnO thin‐film layers is fabricated on indium tin oxide glass. The current–voltage curve of the dual‐function random laser memory (RLM) device exhibits an excellent electrical bistability with a high ON/OFF current ratio (≈107). The random lasing behavior is simultaneously demonstrated by using electrical pumping with the appearance of sharp‐peak emissions and a drastic enhancement of peak intensity. A wide angle‐dependent electroluminescence not only reveals its emitting advantage but also further supports the origin of random lasers. The first proof‐of‐concept presentation of RLM possesses several advantages of dual memory and lasing functions, which enables to open up new avenues to practical applications, such as light emitting memories for electrical and optical communication. This new horizon for the realization of all optical memories should therefore be able to attract academic as well as industrial interests. It is stressed here that the electrical reading of conventional memory array is usually in serial sequence, which limits the maximum data throughput. This hurdle can be overcome by optically readable memory devices.

Whispering-gallery-mode (WGM) resonance manipulated random laser action has been proposed. To illustrate our working principle, lasing characteristics of ZnO nanorods decorated with SiO2 nanospheres have been investigated. It is found that with the assistance of SiO2 nanospheres the emission spectrum exhibits a very narrow background signal with a few sharp lasing peaks and a very small full width at half-maximum of less than 0.3 nm. The differential quantum efficiency (ηd) of random laser action can be greatly enhanced by up to 735%. More interestingly, the wavelength of laser action of ZnO nanorods can be controlled by the decoration of different-size nanospheres. The underlying origin is attributed to the fact that the decorated nanospheres not only enable the generation of WGM resonance and enhance the peak emission intensity but also can serve as scattering centers. Cathodoluminescence mapping images of nanorods decorated with nanospheres and theoretical calculation based on the spherical cavity were utilized to confirm our proposed mechanism. These intriguing features manifest the tunability of mode-controlled random laser action by WGM resonance of nanospheres. Our discovery shown here may open up a new approach for the creation of highly efficient optoelectronic devices.