Lithography is a critical enabling technology for manufacturing micro- and nanoscale devices and structures. The present work explores alternative lithography techniques that pattern photoresist layers through selective thermochemical cross-linking. Microfabricated thin-film heaters are used as precisely defined heat sources to determine the thermal transport properties of photoresist layers and study the kinetics of cross-linking reactions. The present work identifies heating temperature, heating duration,and UV exposure dose as independent control parameters in thermolithography and demonstrates its potential for three-dimensional micro- and nanomanufacturing.

Nanoscale heat conduction across tunnel junctions prepared through natural oxidation of metal electrodes is experimentally studied. The thermal resistance of AlOx tunnel barriers increases linearly with barrier thickness, which is consistent with the prevailing theory of heat conduction in highly disordered materials. Heat conduction across tunnel junctions is strongly impeded by finite thermal resistance at interfaces between barrier and electrode layers, which can be exploited to create superior thermal barrier coatings. The thermal conductivity of nanolaminates consisting of a series of Ta/TaOx tunnel junctions is determined to be well below the minimum thermal conductivity limit. (c) 2005 American Institute of Physics.

Heat transport in polymer nanocomposites reinforced with graphite nanoplatelets (GNPs) is studied using high-precision thermal conductivity measurements. The resistance to heat conduction across interfaces between GNPs and the polymer matrix has a strong effect on energy transport in the nanocomposites. The thermal conductivity is observed to increase when GNPs are pretreated with nitric acid to improve interfacial bonding. The improvement in the thermal conductivity, however, is much smaller than the corresponding improvement in mechanical properties. The thermal interface resistance extracted from the present thermal conductivity data is comparable to that obtained from the previously reported data on carbon nanotube suspensions. (c)2006 American Institute of Physics.