No abstract

The statistics of the RESET voltage (V RESET ) and the RESET current (I RESET ) of Pt/HfO 2 /Pt resistive random access memory (RRAM) devices operated under unipolar mode are analyzed. The experimental results show that both the distributions of I RESET and V RESET are strongly influenced by the distribution of initial resistance in the ON state (R ON ), which is related to the size of the conductive filament (CF) before RESET. By screening the statistical data into different resistance ranges, both the distributions of I RESET and V RESET are shown to be compatible with a Weibull model. Contrary to previous reports for NiO-based RRAM, the Weibull slopes of the I RESET and V RESET are demonstrated to be independent of R ON . This is an indication that the RESET point, defined in this letter as the point of maximum current, corresponds to the initial phase of CF dissolution. On the other hand, given that the scale factor of the V RESET distribution (V RESET63% ) is roughly independent of R ON , the scale factor of the I RESET (I RESET63% ) is inversely proportional to R ON . This is analogous to what was found in NiObased RRAM and it is consistent with the thermal dissolution model of RESET. Our results highlight the intrinsic link between the SET and RESET statistics and the need for controlling the variation of ON-state resistance to reduce the variability of the RESET voltage and current. Index Terms-RESET statistics, resistive random access memory (RRAM), resistive switching (RS).

Silicon-nanowire (Si-NW) array, prepared by an electroless chemical-etching method, shows excellent optical antireflection property over a wide spectral bandwidth. The influence of the wire length on the optical antireflection property and the solar cell performance were studied for both the Si-NW array solar cells and the planar solar cells. The reflectance of NWs solar cells is almost invariable and much lower than that of the planar solar cells but the performance of planar solar cells is the best. Results show the performance of NWs solar cells is strongly affected by some other factors such as surface passivation and electrode-contact property.