The invention relates to chemical reactor templates having channel-like voids parallel to the template's major axis. The channel-like voids may have either micro-scale or nano-scale cross sectional areas. The chemical reactor templates may be used to produce micro- and nano-scale filaments and particles which have a variety of uses. In some embodiments a chemical reactor template of the invention have at least two intersecting channel-like voids substantially parallel to the major axis of said template. The invention also relates to methods for manufacturing a chemical reactor template using sacrificial layers. The chemical reactor templates of the invention may be fabricated to have multiple arrays of channel-like structures as well as vertical elements to provide access to act as contacts for the channel-like voids and materials formed within the template. The invention relates to methods for producing filaments and particles using a chemical reactor template. The filaments or particles are formed within the channel-like void to produce a filament within the channel-like void and may be extruded from the chemical reactor template. Using the chemical reactor templates one can fabricate a wide variety of devices having at least one contact region between a first and second material system over a substrate. Another aspect of the invention is the filaments made using a chemical reactor template of the invention. Accordingly the invention relates to an oriented filament has a nano- or micro-scale cross-sectional area and is prepared within a channel having a nano- or micro-scale cross-section.