Tuning carrier density and phase transitions in oxide semiconductors using focused ion beams

We demonstrate spatial modification of the optical properties of thin-film metal oxides, zinc oxide (ZnO) and vanadium dioxide (VO2) as representatives, using a commercial focused ion beam (FIB) system. Using a Ga+ FIB and thermal annealing, we demonstrated variable doping of a wide-bandgap semiconductor, ZnO, achieving carrier concentrations from 10(18) cm(-3) to 10(20) cm(-3). Using the same FIB without subsequent thermal annealing, we defect-engineered a correlated semiconductor, VO2, locally modifying its insulator-to-metal transition (IMT) temperature by up to similar to 25 degrees C. Such area-selective modification of metal oxides by direct writing using a FIB provides a simple, mask-less route to the fabrication of optical structures, especially when multiple or continuous levels of doping or defect density are required.

Automated summary

In this study, we demonstrated the ability to spatially modify metal oxides using a direct writing approach with a focused ion beam system. By doping a wide-bandgap semiconductor, zinc oxide, we achieved variable carrier concentrations, and by defect engineering a correlated semiconductor, vanadium dioxide, we locally modified its insulator-to-metal transition temperature. This area-selective modification method provides a simple and mask-less route to fabricate optical structures.