Repetition of Negative Differential Resistance in Vertically Integrated Double-barrier Resonant Tunneling Structures

[[abstract]]We propose and demonstrate a novel operation in the vertical integration of double‐barrier resonant tunneling structures (DBRTS’s) in which the negative differential resistance (NDR) region can be repeated. When two DBRTS’s are combined in series, one of which has a higher peak current, a lower valley current, and a larger operation range of voltage in the NDR region than those of the other, the current‐voltage (I‐V) characteristic shows three current peaks instead of the conventional two. This phenomenon is based on the fundamental requirement of current continuity in serially combined devices. This operation provides a method to obtain a large number of current peaks by using less DBRTS’