The AlO_x-based resistive switching memory device is fabricated by an oxidation diffusion process that involves depositing an Al film on an ITO substrate and annealing at 400 °C in a vacuum. An AlO_x interface layer with a thickness of ~ 20 nm is formed as a resistance switching layer. Bipolar and unipolar resistive switching (RS) behaviours are obtained when the compliance current is limited (≥ 1 mA). In the unipolar RS behaviour, the devices fail to perform set/reset cycles at a low temperature (40 K), which suggests that Joule heating is essential for the unipolar RS behaviour. In the bipolar RS behaviour, the abrupt reset transforms into a gradual reset with decreasing temperature, which suggests that Joule heating affects the rupture of the conductive filament. In addition, the conductive mechanisms in the high-resistance state and low-resistance state are revealed by the temperature dependence of the I-V curves. For the low-resistance state, the conduction mechanism is due to the electron hopping mechanism, with a hopping activation energy of 9.93 meV. For the high-resistance state, transport mechanism is dominated by the space-charge-limited conduction (SCLC) mechanism.

Si quantum dots (Si QDs)/SiC multilayers were fabricated by annealing hydrogenated amorphous Si/SiC multilayers prepared in a plasma-enhanced chemical vapor deposition system. The thickness of amorphous Si layer was designed to be 4 nm, and the thickness of amorphous SiC layer was kept at 2 nm. Transmission electron microscopy observation revealed the formation of Si QDs after 900°C annealing. The optical properties of the Si QDs/SiC multilayers were studied, and the optical band gap deduced from the optical absorption coefficient result is 1.48 eV. Moreover, the p-i-n structure with n-a-Si/i-(Si QDs/SiC multilayers)/p-Si was fabricated, and the carrier transportation mechanism was investigated. The p-i-n structure was used in a solar cell device. The cell had the open circuit voltage of 532 mV and the power conversion efficiency (PCE) of 6.28%.

We report herein on the effects of silicon nanowire with different morphology on the device performance of n-SiNW/PEDOT:PSS hybrid solar cells. The power conversion efficiency (PCE) and external quantum efficiency (EQE) of the SiNW/PEDOT:PSS hybrid solar cells can be optimized by varying the length of the silicon nanowires. The optimal length of silicon nanowires is 0.23 μm, and the hybrid solar cell with the optimal length has the V oc of 569 mV, J sc of 30.1 mA/cm2, and PCE of 9.3 %. We fabricated more isolated silicon nanowires with the diluted etching solution. And the J sc of the hybrid solar cell with more isolated nanowires has a significant enhancement, from 30.1 to 33.2 mA/cm2. The remarkable EQE in the wavelength region of 300 and 600 nm was also obtained, which are in excess of 80 %. Our work provides a simple method to substantially improve the EQE of hybrid solar cell in the short wavelength region.