Physical and electrical characterization of atomic-layer-deposited Ru nanocrystals embedded into Al₂O₃ for memory applications

Abstract

Growth of uniformly distributed Ru nanocrystals on Al2O3 is demonstrated via atomic layer deposition using bis(cyclopentadienyl)-ruthenium and oxygen precursors. X-ray photoelectron spectroscopy analyses reveal that metallic Ru nanocrystals were formed in this experiment, and the RuO2 surface is due to oxidation of Ru when exposed to air. The metal-oxide-silicon capacitors with Ru nanocrystals embedded into Al2O3 are electrically measured, exhibiting obvious memory effects such as a large hysteresis memory window of 3.4 V for the sweeping gate voltage of −2.5/ + 8 V and a significant flat-band voltage shift of 3.2 V under the programming of 10 V/1 ms, i.e. an effective electron injection rate as fast as 1.78 × 10−6 C cm−2 ms−1. This relates to the program mechanism of direct tunnelling and a large potential well depth.

Highly Stable Supercapacitors with Conducting Polymer Core‐Shell Electrodes for Energy Storage Applications

“…The survey XPS spectrum of PAni–RuO 2 core–shell nanofibers with 500 ALD cycles of RuO 2 (Figure S4, Supporting Information) shows all the existing elements which match well with EDS measurement. In Figure 4 a, the doublet peaks at 281 and 285.2 eV originate from RuO 2 due to the screened final state, and the doublet peaks at 282.1 and 286.3 eV are also ascribed to RuO 2 due to the unscreened final‐state . Another peak at 285.1 eV is associated with C 1 s peak coming from our carbon fiber support.…”

Defect‐Induced Pt–Co–Se Coordinated Sites with Highly Asymmetrical Electronic Distribution for Boosting Oxygen‐Involving Electrocatalysis

“…Single Ni and Ru were also introduced onto the CoSe 2− x surface through the same photochemical reduction strategy. The existence of Ni and Ru atoms on CoSe 2− x can be confirmed by XPS (Figure S12, Supporting Information), while their contents are verified by ICP‐AES to be 1.1 and 1.9 wt%. From the TEM images no nanoparticles can be observed on CoSe 2− x surface (Figure S13, Supporting Information), but EDS mapping images show that Ni and Ru species are highly dispersive across the CoSe 2− x surface (Figures S14 and S15, Supporting Information).…”

Temperature-Dependent Physical and Memory Characteristics of Atomic-Layer-DepositedRuOxMetal Nanocrystal Capacitors

“…The binding energy peak positions and the separation between the doublets (4.0-4.2 eV) indicate the presence of the RuO x nanocrystals. Zhang et al [14] reported that the peak binding energies of the Ru3d 5/2 electrons for Ru and RuO 2 elements were 280.6 eV and 281.6 eV, respectively. Kaga et al [15] reported that the peak binding energies of the Ru3d 5/2 electrons are 280 eV for the Ru, and 280.8 eV for the RuO 2 films.…”