Thermal-induced chemical modification of palladium acetate on the submicrometer scale by in situ scanning thermal microscopy

In this paper, a new method for studying thermally induced surface reaction s with submicrometer scale resolution is discussed. Thermal-induced chemica l modification of palladium acetate (Pd(OAc)(2)) has been successfully demo nstrated via a scanning thermal microscope that permits sequential temperat ure ramping of its resistive thermal probe. In-situ thermal conductivity co ntrast and dynamic morphological evolutions of the thermal decomposition pr ocess have been monitored with spatial resolution in the submicrometer leng th scale regime to reveal interesting phenomena whereby drastic variations in both thermal conductivity contrast and topography were observed at its t hermal degradation temperature range. At 523 K, thermal-induced modificatio n was found to occur predominantly at the peripherals of the Pd( OAc)(2) is lands. However, almost instantaneous transformation to palladium (Pd) metal took place locally at 553 K within the thermal probe's dwell time of ca. 5 ms at each pixel point. The chemical identity of the newly formed Pd could be identified conveniently due to its distinct thermal conductivity contra st with its surroundings and subsequently confirmed by X-ray photoelectron spectroscopic (XPS) studies.