Enhanced Secondary Electron Emission from Strontium Titanate Films via High-Temperature Annealing

The versatile surface reconstruction mechanisms, tunable surface properties, and exceptional electron emission characteristics of SrTiO3 films have garnered significant research interest. In this study, SrTiO3 films were synthesized on n-Si(100) substrates via radio frequency magnetron sputtering. To evaluate the impact of thermal annealing, the as-deposited films underwent post-deposition annealing in an oxygen ambient at 600 °C, 800 °C, and 1000 °C for a duration of 2 h each. The structural, chemical, and secondary electron emission (SEE) characteristics of the SrTiO3 films were characterized as a function of their high thermal process. Post-deposition annealing induced a significant improvement in crystallinity, which directly correlated with a heightened SEE yield (SEY). Furthermore, composition analysis revealed a marked stoichiometric reconfiguration at the surface, with the Sr:Ti:O ratio evolving from 1:0.32:1.14 to 1:0.22:0.94, suggesting a move toward an Sr-O terminated surface. The Sr-O terminated surface inherent to these SrTiO3 films promotes efficient electron escape due to its reduced work function. Following a 1000 °C annealing process, the peak SEY undergoes a significant shift from 2.11 to 2.76, representing a thermal optimization of the SEE performance by approximately 30.8%. High-temperature annealing enhances the SEE performance of SrTiO3 films, validating their significant potential for electron multiplication applications. This study provides a scalable pathway for developing highly efficient SEE materials with optimized crystalline and surface properties.