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.<
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