Impact of Au Nanocrystal Size and Inter-Nanocrystal Distance on the Storage Characteristics of Memory Devices

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.