Room-temperature observation of resonant tunneling through an AlGaAs/GaAs quasiparabolic quantum well grown by molecular beam epitaxy

We report the first room-temperature observation of resonant tunneling through a double-barrier diode with a 31.5-nm-wide AlGaAs/GaAs quasiparabolic quantum well grown by molecular beam epitaxy. As the bias voltage is scanned from 0 to 4 V, 11 resonant tunneling transitions are observed at room temperature. At 77 K, 13 resonant tunneling transitions are observed; 10 of them show negative differential resistance, and the highest peak-to-valley ratio is 1.4. At 4.2 K, 17 resonant tunneling transitions are observed; 15 of them show negative differential resistance, and the peak-to-valley ratio of the first tunneling peak is 3.6. Computer simulation indicates that for the 17 resonant tunneling transitions, the first 13 are likely due to resonant tunneling through quasibound states in the well, and the remainder are due to resonant tunneling through virtual states.