Download or read book Block Copolymer Self-assembly as a Template for the Generation of Ordered Arrays of Nanowires written by Thomas Garrett Fitzgerald and published by . This book was released on 2008 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Upon self-assembly block copolymers (BCP) form a variety of well-ordered nanometer-sized structures in thin films which satisfy the size requirement for many nanotechnologies. This thesis details the in-depth study of three different BCP systems including the various factors which influence the final film structure, the generation of nanoporous polymer templates and their subsequent use a lithographic etch masks. Chapter 1 provides a general introduction to the principles of BCP self-assembly as well as a brief overview of the current state of this continually expanding field. Chapter 2 focuses on microphase separation within cylinder-forming polystyrene-block-polyisoprene-block-polystyrene BCP thin films. Thermal and solvent annealing are both investigated as potential routes to achieve microphase separation. Following a thermal anneal approach ordered cylindrical structures exhibiting excellent long-range order are achieved using directing effects imposed topographically channelled substrates. Control of film thickness within the channelled structures provides a simple method for control of cylinder orientation (parallel or perpendicular). In Chapter 3 macrophase separation is demonstrated in blends of polystyrene and poly(methyl metacrylate) illustrating the importance of the bonding between polymer units in a polystyrene-block-poly(methyl metacrylate) BCP as a requisite for microphase separation. Both cylinder- and lamellar-forming systems are demonstrated with this BCP, depending on the polymer ratio, and the orientation of the structures can be controlled via polymer-substrate interactions. Variation of molecular weight of the BCP provides a simple means of controlling resultant feature sizes. Reactive ion etching provides a rapid route for the generation of polystyrene template structures which can be subsequently used as positive etch mask to produce arrays of silicon lines. The microphase separation within both polystyrene-block-poly(ethylene oxide) BCP and polystyrene-block-poly(ethylene oxide)/polystyrene blend thin films, induced via solvent annealing, is discussed in Chapter 4. Blends of polystyrene homopolymer and polystyrene-block-poly(ethylene oxide) BCP result in a cylindrical structure rather than the predicted lamellar morphology due to the increased amount of polystyrene present. Selection of the appropriate solvent anneal conditions provides a simple means of controlling the orientation of the final structure. Variation of molecular weight again provides excellent control over feature size, however, if it is too low microphase separation will not occur. Reactive ion etching also provides a rapid route for the generation of polystyrene template structures. Chapter 5 provides a general overview of the various techniques used during the course of this thesis as well as providing supplementary information on calculations and BCP synthesis mentioned in previous chapters.