New resonant-tunneling devices with multiple negative resistance regions and high room-temperature peak-to-valley ratio

A new resonant-tunneling (RT) device with multiple peaks in the current-voltage characteristics is presented. The multiple peaks are obtained by sequential quenching of resonant tunneling through the ground-state resonances of the quantum wells (QW´s) of a number of double barriers (DB´s) in series, thereby producing the peaks at nearly the same current level. Devices with three and five peaks operating at room temperature were implemented using Ga/sub 0.47/In/sub 0.53/As/Al/sub 0.48/In/sub 0.52/As heterostructures. The current-voltage characteristics of these devices indicate peak-to-valley ratios of 5:1 at room temperature and as high as 18:1 at 77 K. These devices are useful for multiple-valued logic and applications involving reduced circuit complexity.<>