Photothermoelectric detection of gold oxide non-thermal decomposition and related studies*

Controlling morphology and composition via nanoscale structuring gives opportunities to improve the thermoelectric properties of materials for energy conversion and photodetection. In this study, we report the detection of the decomposition of metastable gold oxide via open circuit photothermoelectric voltage detection on thin-film Au nanowire devices as a function of the position of an optical heat source. A focused laser beam is used to locally heat the metal nanostructure. The first-scan enhanced photovoltage correlates with a reduction of the electrical resistance of the nanostructure back to pre-oxygen-exposure levels. These experiments demonstrate that combined optical and electronic measurements can provide a window on surface-sensitive photochemical processes. Besides the photothermoelectric voltage detection of gold oxide, we also report preliminary data on the thermoelectric properties of Au nanowires via other surface modification methods includes self-assembled monolayer formation.