Size-induced metal-to-semiconductor transition and room temperature sequential resonant tunneling in La0.5Sr0.5CoO3−δ quantum dots embedded in La0.5Sr0.5CoO3−δ nanotubes

The sequential resonant tunneling in La0.5Sr0.5CoO3−δ (LSCO) semiconductor quantum dots (QDs) arrays were observed by current-voltage measurements under room temperature. A series of spikelike current peaks are found, which are resulted from the accumulation and depletion of electrons tunneling through the QDs embedded in insulated barriers. Temperature dependent onset-voltage blueshift and number variation in current peaks are also observed. These results confirm the size-induced metal-to-semiconductor transition in LSCO.