Au(Si)-filled $β-Ga2O3$ nanotubes as wide range high temperature nanothermometers

Au(Si)-filled $β-Ga2O3$ nanotubes were fabricated by an effective one-step chemical vapor deposition method. The Au(Si) interior was introduced by capillarity. Linear thermal expansion of Au(Si) with a coefficient of thermal expansion (CTE) as high as $1.5×10−4(1∕K)$ within single crystal $Ga2O3$ shell up to $800°C$ was observed by in situ transmission electron microscopy. The high CTE is correlated to partial melting of Au(Si). As $Ga2O3$ possesses excellent thermal and chemical stability, the structure can be used as a wide range high-temperature nanothermometer within localized regions of nanosystems.