Resonant tunneling through single InAs quantum dot at room temperature

Transport properties of freestanding InAs quantum dots on GaAs(001) are investigated by means of conductive atomic force microscopy. Resonant tunneling through the hole state of valence-band of single quantum dot is observed at room temperature. The threshold bias for resonant tunneling is related with the dot size, while the amplitude of tunneling current changes little when the height of dot varies from 2 to 10 nm.