  Molecular beam epitaxy is employed to manufacture self-assembled InAs/AlAs
quantum-dot resonant tunneling diodes. Resonant tunneling current is
superimposed on the thermal current, and they make up the total electron
transport in devices. Steps in current-voltage characteristics and peaks in
capacitance-voltage characteristics are explained as electron resonant
tunneling via quantum dots at 77K or 300K, and this is the first time that
resonant tunneling is observed at room temperature in III-V quantum-dot
materials. Hysteresis loops in the curves are attributed to hot electron
injection/emission process of quantum dots, which indicates the concomitant
charging/discharging effect.
