Gold nanoparticle density-multiplication by tuning block copolymer self-assembly processes toward increased charge storage

We describe a simple and versatile approach for enhanced nanoparticle density multiplication through the block copolymer self-assembly technique for application in memory devices. Templates of block copolymers with functional groups directed the selective electrostatic self-assembly of the pre-formed gold nanoparticles to form gold nanocluster arrays. By simply increasing the density of the polymer templates by manipulating the spin coating conditions, a lateral increase in the nanoparticle density is observed. The significance of the particle density multiplication was best observed when they were used as charge storage centers in flash memories. Minimization of the pitch (or maximization of the template density) resulted in a maximum memory window of about 1.63 V, with a charge trap state density of 4.93 × 10 11 cm −2 in the gold nanocluster arrays. The reported approach offers exciting opportunities to fabricate multicomponent nanostructure-based memory devices tailored for enhanced memory performance. In addition, the nanoparticle density can be increased significantly further when combined systematically with the hierarchical block copolymer self-assembly approach.