Resistive switching in FTO/CuO-Cu2O/Au memory devices

Memristors are considered to be next-generation non-volatile memory devices owing to their fast switching and low power consumption. Metal oxide memristors have been extensively investigated and reported to be promising devices, although they still suffer from poor stability and laborious fabrication process. Herein, we report a stable and power-efficient memristor with novel heterogenous electrodes structure and facile fabrication based on CuO-Cu2O complex thin films. The proposed structure of the memristor contains an active complex layer of cupric oxide (CuO) and cuprous oxide (Cu2O) sandwiched between fluorine-doped tin oxide (FTO) and gold (Au) electrodes. The fabricated memristors demonstrate bipolar resistive switching (RS) behavior with a low working voltage (~1 V), efficient power consumption, and high endurance over 100 switching cycles. We suggest the RS mechanism of the proposed device is related to the formation and rupture of conducting filaments inside the memristor. Moreover, we analyze the conduction mechanism and electron transport in the active layer of the device during the RS process. Such a facile fabricated device has a promising potential for future memristive applications

InGaAs Quantum Well Grown on High-Index Surfaces for Superluminescent Diode Applications

The morphological and optical properties of In0.2Ga0.8As/GaAs quantum wells grown on various substrates are investigated for possible application to superluminescent diodes. The In0.2Ga0.8As/GaAs quantum wells are grown by molecular beam epitaxy on GaAs (100), (210), (311), and (731) substrates. A broad photoluminescence emission peak (~950 nm) with a full width at half maximum (FWHM) of 48 nm is obtained from the sample grown on (210) substrate at room temperature, which is over four times wider than the quantum well simultaneously grown on (100) substrate. On the other hand, a very narrow photoluminescence spectrum is observed from the sample grown on (311) with FWHM = 7.8 nm. The results presented in this article demonstrate the potential of high-index GaAs substrates for superluminescent diode applications

Effects of high‑temperature annealing on the performance of copper oxide photodetectors

Copper oxide thin films are grown using copper nanofilms oxidized at high annealing temperatures. The thin film crystallinity and surface morphology are probed using the X-ray diffractometer and scanning electron microscopy, indicating that the crystalline quality of the copper oxide thin films is improved by increasing the annealing temperature. Under ultraviolet–visible light illumination, the fabricated device with thin films annealed at 900 °C and the corresponding bandgap of 2.8 eV demonstrates the high responsivity of 15.1 A/W and maximum detectivity of 4.52 × 1012 cmHz1/2/W. The photosensitivity of thin films annealed at 900 °C is more than ten times higher than that of thin films annealed at 800 °C. The fabricated device works as a visible–ultraviolet photodetector and maintains uniform and stable performance for a tested period of eight weeks