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The charge-storage characteristics of charge trapping memory devices containing different sizes of Au nanocrystals (NCs) sandwiched by Al2O3 tunneling and blocking layers are studied. A strong impact of both Au NC size and inter-NC distance on the charge trapping capability of the devices is observed. The total surface area of Au NCs associated with Au NC size is supposed to be a key factor in the charge-storage capability, and the device with larger size of Au NCs and a suitable inter-NC distance will possess better charge trapping capability. Variable range hopping as the lateral charge loss mechanism is considered as the main reason for the decrease of the charge trapping capability when Au NCs grow and overlap neighbors. [ABSTRACT FROM AUTHOR]

Sb2Te films with different Ti contents (TixSb2Te) are derived via the target-attachment method by using the magnetron sputtering technique. The effects of the Ti content on the phase change characteristics and the microstructures are investigated by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy and atom force microcopy. Resistance-temperature measurements are carried out to reveal the enhanced crystallization temperature of TixSb2Te films, indicating a better thermal stability in such films. Both the activation energy and the temperature for 10 y data retention increase with increasing the concentration of Ti. It indicates that the crystallization of the amorphous Sb2Te film could be suppressed by the introduction of Ti. The improvement of crystallization temperature and the thermal stability of the amorphous Sb2Te film results from the introduction of Ti in Sb-Te bond that decreases the binding energy of Sb 4d and Te 4d. [ABSTRACT FROM AUTHOR]