Demonstration of a reflective coupling diode in a coupled waveguide structure

Despite the difficulty in fabrication, resonant tunneling diodes ~RTD! have found a great deal of usage in the analog, digital, and mixed signal realms as a means of increasing the speed of signal processing circuitry or in reducing the static power dissipation in the circuitry. Nevertheless, RTDs suffer from their nonplanar structure. In this paper, we present a planar diode which operates via coupling of injected electron modes or a reflective coupling diode from an input waveguide to a corresponding output waveguide in a semiconductor hetrostructure. We demonstrate that the I – V characteristics of this structure exhibit the characteristic negative differential conductance of RTD current–voltage characteristics. The resultant behavior of this planar device shows great promise for eventual implementation in ultrasmall high-speed circuitry. © 2003 American Institute of Physics. @DOI: 10.1063/1.1563827#