The present disclosure is directed to systems for tuning nanocube plasmonic resonators and methods for forming tunable plasmonic resonators. A tunable plasmonic resonator system can include a substrate and a nanostructure positioned on a surface of the substrate. The substrate can include a semiconductor material having a carrier density distribution. A junction can be formed between the nanostructure and the substrate forming a Schottky junction. Changing the carrier density distribution of the semiconductor material can change a plasmonic response of the plasmonic resonator.