Photophysical processes in low-fluence UV laser–material interaction and the relevance to atomic layer processing



Atomic-scale material-processing tools must be developed to allow the in situ synthesis of complex, nanometre-scale, multilayer structures. These processing tools must be cost-effective, extendible to large-area surfaces and adaptable to realistic manufacturing equipment. Presented here are experimental results on the photophysical processes in low-fluence UV laser radiation of surfaces. The results suggest that atomic-level synthesis/modification of materials is possible by the laser-induced desorption by electronic excitation (LIDEE) process. The processing action employs resonance behaviour to gain species selectivity in the products desorbed. It naturally lends itself to automation (pulsed processing) and is designed for manufacturing laser systems currently used in materials processing. In addition, no potential limitations exist on the surface area which can be processed. Presented are the experimental data using crystalline Al and Bi2Sr2Ca1Cu2O8 targets along with supporting results from Ag and W targets. The results are interpreted in the light of photodesorption models which best support the data. As a conclusion we present an outline of how the LIDEE process might be used as a nanometre-scale material-processing tool.