Growth of Fibers
As demonstrated in the preceding chapter, lateral growth of photothermally deposited spots saturates for long laser-beam illumination times, τ ℓ. With certain systems and within certain parameter ranges, this saturation is accompanied by an increase in axial growth and the formation of a fiber along the axis of the laser beam. A typical fiber is shown in Fig. 17.0.1 with the example of Si. Two phases of growth can be observed. Near the onset, the deposition rate depends strongly on the physical properties of the substrate. Under quasi-stationary conditions, as characterized by a constant fiber diameter, the temperature in the tip becomes independent of substrate material and time. For this reason, the temperature can be measured in situ with high precision.
KeywordsConvection Silane Hydrocarbon Tungsten Emissivity
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